While working on a standardized test, where one of the questions suggests to choice the only one correct answer, the following sentence seems to me a bit confusing:
Long hours and unsociable shifts _____ take their toll on health, relationships and family life.
B (are able to)
The only correct answer for this question is C. However, it seems to me that B is also possible. As far as I understand, "can" is preferred here because it is used more frequently and the question is more about general capability. But these arguments are not seem strong enough to claim C as the only right answer.
So I am asking if you can clarify why this answer is so preferable and if you can "give a taste" about how much unnatural is B variant sound.