Constance Horner,chief of the United States government's personnel agency ,has recommended that the use of any dangerous or illegal drug in the five years prior to application for a job be grounds for not hiring an applicant.

A the use of any dangerous or illegal drug in the five years prior to application for a job be grounds for not hiring an applicant

B  any dangerous or illegal drug ,if used in the five years prior to applying for a job ,should be grounds for not hiring an applicant

C   an applicant's use of any dangerous or illegal drug in the five years prior to application for a job be grounds not to hire them .

D  an applicant's use of any dangerous or illegal drug in the five years prior to applying for a job are grounds that they not be hired

E   for five years prior to applying for a job ,an applicant's use of any dangerous or illegal drug be grounds for not hiring them

答案为什么是a啊？

recommended that- 后用虚拟语气

be ground for doing 固定用法