Answer:
The pronoun that agrees with the indefinite pronoun many in the sentence Many of the castles are no longer home to___lords and ladies is a. their.
Step-by-step explanation:
Most indefinite pronouns are either singular or plural. In both cases, the pronoun should agree in number and gender with the rest of the elements of the sentence. In this case, the pronoun many -plural- agrees with their, that is the only answer that shows plural form.