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: A billiard ball has a greater mass then a basketball. Question: Which ball has a stronger field of gravity? (A) billiard ball (B) basketball
billiard ball