That's correct! The indefinite pronoun "either" can be singular or plural depending on the context. When used to refer to two options or choices, "either" is considered singular. For example, "Either option is fine with me." However, when used in a sentence that includes more than two options, "either" is considered plural. For example, "He can choose either of the three options." So, in summary, option C, "singular or plural depending on the context," is the correct answer.
