Which sentence shows correct subject-verb agreement with a singular or plural subject using "or"?

Which sentence shows correct subject-verb agreement with a singular or plural subject using "or"?

• A. Either the student or the teachers is mistaken.
• B. Either the student or the teachers are mistaken.
• C. Either the student or the teacher are mistaken.
• D. Either the teachers or the student are mistaken.

Answer: (B)

When two subjects are joined by or, the verb must agree with the noun closest to it. In the phrase “Either the student or the teachers,” the closest subject to the verb is “teachers,” which is plural. So the verb should be plural: are. Therefore, the sentence using are is the correct form.

If you used is, you’d be forcing singular agreement on a plural noun that sits next to the verb, which breaks the rule. If the closest noun were singular, you’d use is (for example, if it were “Either the student or the teacher”), but in this case the closest noun is plural, so are is correct.