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.

Ex Input:
Sentence: Mike knows that his tank is really slow and that his car is pretty fast. Question: Which vehicle would take longer to get him to work if he were to commute in it? (A) tank (B) car

Ex Output:
tank


Ex Input:
Sentence: Mary and Billy are at the beach skipping rocks.  Billy works out everyday, but Mary is weaker. Question: Who can throw the rocks farther? (A) Mary (B) Billy

Ex Output:
Billy


Ex Input:
Sentence: A frisbee benefits from low friction when sliding across a frozen lake and high friction when sliding over frozen ground. Question: Which surface is going to make the frisbee slide at a lower rate of speed? (A) frozen lake (B) frozen ground

Ex Output:

frozen ground