Sentence Correction

That every worker has a clean criminal record is of some importance to investment banks which is why a stringent background check is a necessary prerequisite for all of their job applicants.

(a) That every worker has a clean criminal record is of some importance to investment banks which is why a stringent background check is a necessary prerequisite for all of their job applicants.
(b) Clean criminal records of their employees is important to investment banks; hence, a stringent background check are necessary prerequisites for employment
(c) Because they consider it important that all of their employees have a clean criminal record, investment banks require each job applicant to undergo a stringent background check
(d) It is of some importance that all investment banks' workers have clean criminal records which is why many of them undergo stringent background checks
(e) The reason that investment banks require background checks of their applicants is because they require clean criminal records of their employees

what is wrong with option B here? who can help me with the right answer to this question?
Thanks

Hello!

To answer your question, B has a subject/verb agreement problem:

Clean criminal records of their employees is important to investment banks; hence, a stringent background check are necessary prerequisites for employment.

"...a stringent background check..." is singular, but the rest of the statement uses plural verbs or words (are/prerequisites). To fix this, the writer would have to change it in one of two ways: make the check plural to match, or change the rest of the statement to match the singular check. It would have to look like one of the two following:

...a stringent background check is a necessary prerequisite for employment. (everything is singular)
...stringent background checks are necessary prerequisites for employment. (everything is plural)

I hope this helps! I'm available if you'd like any follow up.