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: Debbie was exercising with a giant exercise ball. It rolled out from under her and rolled on the frictionless gym floor. She retrieved it and started again, but this time it rolled onto a rough rubber mat. Question: Which surface was smoother? (A) gym floor (B) rubber mat
gym floor