Modal Verbs – ‘Can’ vs ‘Be Able To’ in Present Tense

can-vs-be-ablemeaningmodal-verbs

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.
A (must)
B (are able to)
C (can)
D (shouldn't)

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.

Best Answer

Long hours and unsociable shifts are not able to act on their own in taking their toll on health, relationships and family life.

They require a person subject to health, relationships and family life. Therefore the most logical answer is C. A and D are non-relevant or opinionated.