(A) Incorrect. Both parts of this option are incorrect.

The first is not presented as evidence. It is an opinion of the author. Moreover, there is no data in the argument that confirms this opinion. (We might be tempted to believe that there is evidence to support this portion. Even then, we can comfortably see that the first portion is not confirmed by any data.)

While the second portion could be considered a hypothesis, the first portion (“this evidence”) does not undermine the second. In fact, the first portion supports the second. 

(B) Correct. Both parts of this option are correct.

The first is indeed an opinion. And there is no supporting evidence for this portion.

Let’s spend some time here. There could be concerns that either of the following supports this boldfaced portion:

1. The four holes “are spaced in exactly the right way for playing the third through sixth notes of a diatonic scale”

Is the fact that the flute has four holes that are spaced in a particular way evidence of more holes? It isn’t. Let’s try to understand why not.

Let’s consider the following situation:

Say, walking down a street, a person sees a fragment of a piece of paper with the letters ‘ohn Smit’ on it. Say the person thinks: these letters exactly fit the middle portion of a common name: John Smith. And then the person concludes: it looks reasonable to say that the entire piece of paper must have had more letters.

What must this person walking down the street have assumed to make the above conclusion?

The person must have assumed that the complete piece of paper spelled out John Smith. (Think about it. How else could he have made the above conclusion?)

The train of thought:

1. Oh look, a fragment of a piece of paper with the letters ‘ohn Smit’ on it.
2. Hmm, these letters exactly fit the middle portion of a common name: John Smith.
3. Oh then, the complete piece of paper must have spelled out John Smith. (assumption)
4. The entire piece of paper must have had more letters. (conclusion)

Similarly, here’s another situation, closer to the one in the passage:

Say, walking down a street, a person with basic knowledge of flutes and the diatonic scale sees a fragment of a flute that has four holes spaced in exactly the right way for playing the third through sixth notes of a diatonic scale lying on the road. Say the person realizes that the four holes are spaced exactly like the middle holes of a diatonic scale. And then the person concludes: the entire flute must have had more holes.

What must this person have assumed to make the above conclusion about the flute? The person must have assumed that the entire flute must have played a diatonic scale.

This guy’s complete train of thought:

1. Oh look, a fragment of a flute with four holes in it.
2. Hmm, the four holes are spaced exactly like the middle holes of a diatonic scale.
3. Oh then, the entire flute must have played a diatonic scale. (assumption)
4. Therefore, the entire flute must have had more holes.

So, the spacing of the four holes supports the conclusion that the flute has more holes only if the person makes the above assumption.

In the actual argument, for the spacing of the four holes to support the claim that the flute had more holes, the author MUST have assumed that the flute was built to play the diatonic scale. I.e, the Neanderthals must have used a diatonic musical scale.

Basically, for the previous portion to support the first boldfaced portion, the author must have assumed what he went on to conclude – the conclusion of the given argument is that Neanderthals used a diatonic scale. Does it make sense for us to say that the author  first assumed something that he eventually concludes? Not really.

Let’s note one more aspect. The argument starts with the question of when the diatonic scale originated. Would the author then assume that the scale was already in existence during the Neanderthal period if he’s actually set out to figure out when the scale originated? Does not seem logical either.

For these reasons, the first boldfaced portion is not supported by the portion that precedes it.

2. “[T]he flute was made from a bone that was long enough for these additional holes to have allowed a complete diatonic scale to be played”

Let’s look at this portion carefully:

Does it state that ‘the flute was made from a bone long enough to have seven holes’? It doesn’t.

It states that the intact bone was long enough for THESE additional holes (referring to the holes mentioned before the ‘and’) to have allowed a complete diatonic scale to be played. This portion builds on top of what was mentioned in the first clause in this sentence.

The entire flute must have had more holes, and, what’s more, the intact bone from which the flute was made was long enough for these additional holes (‘the entire flute must have had additional holes’ is already established by this point) to have played a complete scale.

The precise wording of this portion highlights that it does not support the first boldface portion, rather builds on top of it.

The second portion is indeed the main conclusion of the argument. The first portion does support it.

(C) Incorrect. Part one is incorrect, part two is correct.

Wrong on so many levels. There isn’t any ‘position’ in the passage ‘against which the argument is directed’. The argument builds in one direction – to finally conclude that the Neanderthals probably used a diatonic scale. The first boldfaced portion does not ‘undermine’ any ‘position’. It supports the main conclusion. It is not a ‘discovery’. It is an opinion.

The second part is correct. The second portion is indeed the main conclusion of the argument.

(D) Incorrect. Part one is incorrect, part two is correct.

This is the option that test-takers most commonly select for this question (At the time of posting this question, 51% test-takers had selected this option on GMATClub). As discussed in the explanation of option B, the first portion is merely an opinion without any evidence to support it.

The second part is correct.

(E) Incorrect. Both parts of this option are incorrect.

The first portion does support the main conclusion. However, it does not provide any ‘evidence’. It simply states an opinion.

The second portion IS the main conclusion of the argument. It is not a subsidiary conclusion.