Answer:
The dark wizards were not about to let Harry Potter get the best of them.
Explanation:
A pronoun is one of the eight (8) parts of speech in English language and it can be defined as a word that is used to replace a noun in a sentence i.e it substitutes a noun and noun phrases in a sentence. Some examples of a pronoun are he, she, you, I, who, it, them, ours, someone, whose, everybody, many, few, each, herself, himself, whoever, those, etc.
In English language, a subject can be defined as a person, thing, idea or place that performs an action.
Also, 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 (one) and if the subject is plural; the pronoun must be plural (more than one).
Furthermore, a pronoun referring to a singular subject should be in singular form while when it's referring to more than one (plural) subject, it should be in plural form; so as to connote an agreement of words (concord).
<em>In this context, the sentence that demonstrates a correct pronoun usage is; "The dark wizards were not about to let Harry Potter get the best of them."</em>
<em>Wizards is a plural subject and as such should be replaced with a pronoun that connotes plurality such as them.</em>