Instructions: 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.
Input: Sentence: A pebble sinks smoothly into a pond, but not into an ocean. Question: Which surface will the pebble plunge deeper into? (A) pond (B) ocean
Output:
pond