Which word correctly fills the blank in the sentence: Applicants should know the requirements of a job before filling out the application. If a job requires extensive interaction with children, an employer may require that - blank - undergo a background check.

• A. applicants
• B. applicant
• C. applying
• D. apply

Answer: (A)

When a sentence uses may require that, the verb in the clause after that stays in its base form, and the subject of that clause should clearly refer to the people involved. Here, the employer is talking about the people who would undergo the background check—the applicants. Since this refers to more than one person, the plural noun applicants fits best, giving the natural flow: that applicants undergo a background check. Using a singular form like applicant would restrict to one person, and applying or apply are verbs, not suitable nouns for the subject of undergo.