Bread and butter _______ wholesome food.

When two nouns (bread and butter) joined by 'and' talk about a single collective idea, we use the singular verb. Let us explore the given options: The verb 'is' is the third-person singular present verb. The verb 'are' is the second person singular present and first, second, third person plural present verb. The verb 'was' is the first and third-person singular past verb. The verb 'were' is the second person singular past, plural past, and past subjunctive verb. Hence, the correct answer is option 1.