Given the task definition and input, reply with output. You are given a sentence, a question and two answer options ('A' and 'B'). Your task is to find the correct answer (return the string of the correct option, not 'A' or 'B') for the given question.

Sentence: Mitch is rolling wagons down a hill at the same time. The red wagon goes to the bottom of the hill, but the black wagon stops halfway down the hill. Question: Which wagon was slower? (A) red wagon (B) black wagon
black wagon