The more frequently employees take time to exercise during w

[Applebus]

The more frequently employees take time to exercise during working hours each week, the fewer sick days they take. Even employees who exercise only once a week during working hours take less sick time than those who do not exercise. Therefore, if companies started fitness programs, the absentee rate in those companies would decrease significantly.

Which of the following, if true, most seriously weakens the argument above?

A. Employees who exercise during working hours occasionally fall asleep for short periods of time after they exercise.
B. Employees who are frequently absent are the least likely to cooperate with or join a cooperate fitness program.
C. Employees who exercise only once a week in their company's fitness program usually also exercise after work.
D. Employees who exercise in their company's fitness program use their working time no more productively than those who do not exercise.
E. Employees who exercise during working hour take slightly longer lunch breaks than employees who do not exercise.

Source GMAT PREP

My reason
A : Out of scope
B : For me out of scope
C : It may show that employee who exercises once a week is not representative because if exercise after work is a factor that lower the absentee rate and exercise at company does not help, this argument is not convincing.
D : Out of scope
E : Out of scope

But the OA is B

Please correct my reasoning with B and C.
I looked for this question in the forum but I did not find it. If this question has been already posted, please give a link and delete this topic.

[RonPurewal]

the program is intended to reduce the number of days when workers are absent.
choice B tells us that the workers who miss the MOST days—i.e., the workers who most strongly influence the statistic of 'days missed'—are likely to opt out of the program.
if that is true, then the program is MUCH less likely to have a 'significant' effect on that statistic.

analogy:
say i want to keep teenagers out of street gangs.
as an alternative to the gangs, i plan to start an after-school sports program.
if you tell me "the kids with the highest risk of joining a gang will, in general, NOT be interested in after-school sports", then i can be pretty sure that my program will (mostly) fail.

[RonPurewal]

choice C is irrelevant to this argument, because this argument is based exclusively upon the frequency with which "employees take time to exercise during working hours each week".
in other words, this correlation specifically excludes any exercise that takes place outside working hours.

[Applebus]

Hi Ron,
Thank you very much, it is a really good explanation. I clearly understand.

[RonPurewal]

you're welcome.