Final answer:
The sentence with correct subject-verb agreement is (Option C) "Neither Bill nor the Smiths have called."
Step-by-step explanation:
- In English, the subject and verb in a sentence must always agree in number; meaning a singular subject must be paired with a singular verb and a plural subject must be paired with a plural verb. When looking at the provided options, options A, B, and D do not have proper subject-verb agreement.
- Option A should use 'Have' to agree with the plural subject 'you', option B should use 'is' to agree with the singular phrase 'a reason', and option D should use 'has to' to agree with the singular phrase 'Every room'.
- However, option C correctly matches the plural verb 'have' with the compound plural subjects 'Bill nor the Smiths'. Therefore, the sentence in which the subject and verb agree is C) Neither Bill nor the Smiths have called.