The core of this argument is that because enthusiasm for hobbies may indicate that the candidate is less concerned with work than with play, personnel managers should not inquire about a candidate's hobbies.
Just because such enthusiasm may have uncertain results regarding one aspect of a candidates job performance does not mean we can't use questions about hobbies to learn other important factors relating to job performance.
We're asked to find the answer choice that does not reflect a flaw in the argument.
(A) undermines the conclusion that personnel managers should not inquire inquire about hobbies.
(B) supports the conclusion that personnel managers should not inquire about hobbies. The reason being that personnel managers are not likely to get useful information, because they cannot count on getting honest answers.
(C) undermines the conclusion that personnel managers should not inquire inquire about hobbies.
(D) undermines the conclusion that personnel managers should not inquire inquire about hobbies.
(E) undermines the conclusion that personnel managers should not inquire inquire about hobbies.
Each of the incorrect answer choices offers a reason why personnel managers would want to inquire about hobbies, whereas the last actually works in the opposite direction by supporting the conclusion that they should not ask such questions.