Answer:
A. Dwight is a person who has trouble making up his mind.
Step-by-step explanation:
A pronoun is one of the parts of speech in English language and it can be defined as a word that replaces a noun in a sentence. Some examples of a pronoun are he, she, you, I, who, it, them, ours, etc.
In English language, a subject can be defined as the person, thing, idea or place that performs an action.
A subject-pronoun agreement refers to the situation in which there is an agreement between a subject and a pronoun in terms of number.
This ultimately implies that, if a subject is singular, its pronoun should also be singular and if the subject is plural, the pronoun must be plural.
Further, a pronoun referring to the singular subject should also be in singular form, so as to connote an agreement of words (concord).
Hence, the sentence which uses pronoun correctly is; Dwight is a person who has trouble making up his mind.