Answer:
C. The popcorn was burned in the microwave, so it did not taste right.
Step-by-step explanation:
The antecedent is the noun used in the sentence, which is in that same sentence afterward replaced by the fitting pronoun. Pronoun-antecedent is that pronoun that is used. Pronoun-antecedent should be in the correct form, meaning incorrect gender or number. Singular nouns should have singular pronouns, while plural ones are replaced by plural pronouns.
All the sentences beside the C example have a plural noun (sauces, icicles, puppies) which is later replaced with a singular pronoun (it). The fitting pronouns should be them for A and B examples, and they for D example.
Noun popcorn does refer to more than one piece of popcorn, but it does not change in the plural state and is treated the same as singular nouns (like rain, snow, wheat, corn, etc.). Therefore, the pronoun which is fitting to replace the antecedent popcorn should be singular, which means it.