You will be given a definition of a task first, then some input of the task.
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: Samuel dropped a small light pebble and a large heavy rock off a cliff at the same time. Question: Which one hit the ground at the bottom of the cliff first? (A) the pebble (B) the large rock
Output:
the large rock