Question
Which of the following most logically completes the argument given?
Asthma, a chronic breathing disorder, is significantly more common today among adult competitive swimmers than it is among competitive athletes who specialize in other sports. Although chlorine is now known to be a lung irritant and swimming pool water is generally chlorinated, it would be rash to assume that frequent exposure to chlorine is the explanation of the high incidence of asthma among these swimmers, since __________.
Option A
Option B
Option C
Option D
Option E
(This question is from Official Guide. Therefore, because of copyrights, the complete question cannot be copied here. The question can be accessed at GMAT Club)
Solution
Understand the Passage
Asthma, a chronic breathing disorder, is significantly more common today among adult competitive swimmers than it is among competitive athletes who specialize in other sports.
This statement compares the incidence of asthma between competitive swimmers and other competitive athletes. The incidence of asthma is significantly higher in competitive swimmers than it is in other competitive athletes.
Although chlorine is now known to be a lung irritant and swimming pool water is generally chlorinated
If we read this part in context of the above statement, we’ll understand that this statement seems to provide a reason for the first statement. The reason for higher incidence of asthma among competitive swimmers could be the presence of chlorine in swimming pools.
However, since this clause forms a part of ‘Although’, we can expect the following clause to say something in the opposite direction.
it would be rash to assume that frequent exposure to chlorine is the explanation of the high incidence of asthma among these swimmers, since __________.
As expected, this part says (something opposite) that the presence of chlorine in swimming pools should not be assumed to be the cause of higher incidence of asthma among these swimmers. This part ends with ‘since’. So, we need to find a reason why the presence of chlorine shouldn’t be assumed to be the cause.
Predict an Answer
Any alternate cause for the higher incidence of asthma in competitive swimmers would be an answer. Also, any option that suggests that competitive swimmers are sufficiently guarded against the harmful effects of chlorine in swimming pools will also be an answer.
Option Analysis
(A) Incorrect. The first thing to notice here is that this option talks about competitive-athlete-category as a whole. It doesn’t distinguish between competitive swimmers and other competitive athletes. Since the whole point of the passage is to explain the higher incidence of asthma among competitive swimmers vis-à-vis other competitive athletes, an option that doesn’t distinguish between these two categories of competitive athletes will always be irrelevant.
Even if we change ‘competitive athletes’ to ‘competitive athletes who are not competitive swimmers’, the option will still be incorrect. The changed option means that we don’t have a biased population of young people coming into other competitive athletics (biased here means more likely to have asthma). The option thus means that there is no reason to expect a higher than normal incidence of asthma among competitive athletes who are not swimmers. However, this option fails to give any reason for higher incidence of asthma among competitive swimmers or any reason why the presence of chlorine cannot lead to higher incidence of asthma among competitive swimmers.
Even if we change ‘competitive athletes’ to ‘competitive swimmers’, the option will still be incorrect. Rather, in this case, the negation of this option will be a possible answer.
(B) Incorrect. This option is in the opposite direction to the correct answer. If other competitive athletes are rarely exposed to chlorine and, we know that, competitive swimmers are frequently exposed to chlorine, then it seems reasonable to expect that chlorine leads to higher incidence of asthma among competitive swimmers. This expectation is opposite to the stated last line.
(C) Incorrect. For the same reason as stated in option A. This option talks about competitive-athletes-category as a whole.
(D) Correct. If physicians routinely recommended competitive swimming to children with asthma, then we can expect a higher proportion of people with asthma in competitive swimming than in other sports. Thus, this option provides an alternate reason for the higher incidence of asthma among competitive swimmers. A higher proportion of people joining competitive swimming have asthma than joining other competitive athletics. This can explain the higher incidence of asthma among competitive swimmers than among other competitive athletes. Thus, the presence of chlorine in swimming pools may not be the explanation for the higher incidence of asthma among competitive swimmers.
(E) Incorrect. Again, this option is incorrect for the reason stated in option A: it talks about the category of competitive athletes as a whole. In case no distinction is made between competitive swimming and other competitive sports, then whatever is applicable for competitive swimming must be applicable for other competitive sports too. Thus, this scenario will not give us any reason to expect a higher incidence of asthma among competitive swimmers.
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