The phrase that completes the sentence is C. Enchiladas or spaghetti.
This phrase is the only one that keeps a correct subject- verb agreement since the second noun is <em>uncountable</em>, so it corresponds with the singular form of the verb be. While enchiladas is a plural noun, the noun that must match with the verb is the one that is <em>nearer the verb</em>, in this case, spaghetti.
