Choose the past, third person plural form of to have.

you had
we will have
they will have had
they had

The correct answer is D. They had

Explanation:

In grammar, pronouns are classified into the first person (I and We), second person (you) and third person (she, he, it, they). Additionally, in the case of the third person, singular pronouns include she, he, it and the only plural third-person pronoun is they. Moreover, the simple past verb form for the verb "have" is "had" for all the pronouns. Considering this, in this case, the correct answer is "They had" because this includes the third person plural pronoun and also the correct verb form of the verb "have" in the past.