Which grammar error can be solved by changing the subject case (singular or plural)?

Changing the subject case can effectively resolve pronoun-antecedent disagreement. This type of grammatical error occurs when a pronoun does not agree in number or gender with the noun (antecedent) it refers to. By adjusting the subject case—such as switching a singular antecedent to a plural form or vice versa—you can ensure that both the pronoun and its antecedent refer to the same number, thereby achieving agreement.

For example, if the antecedent is singular and the pronoun used is plural, adjusting the antecedent to match the plural form can eliminate the disagreement. This aligns the grammar correctly and maintains clarity in the sentence.

In contrast, verb tense agreement errors relate to the timing of actions expressed by the verbs, which typically involve ensuring that the tenses used match across a sentence, but do not pertain to pronoun usage. Subject-verb agreement focuses on matching the subject's number with the verb, without necessarily involving pronouns. Lastly, modifier placement deals with the positioning of descriptive words and phrases within a sentence, which does not relate directly to subject case changes.