You are given a sentence, a question and two answer options ('A' and 'B'). Your task is to find the correct option for the given question. Write down the answer index: 'A' or 'B'.

Example input: Sentence: Jacob and Benny are squatting at the gym. Jacob has thin frail legs and Benny has big strong legs. Question: Who squats less weight? (A) Jacob (B) Benny
Example output: A
Example explanation: Typically, people with thin frail legs squat less weight than people with big strong legs, so the answer is A.
Q: Sentence: Mercury is less massive than Mars. Question: Which one has the weaker gravitational force? (A) Mars (B) Mercury
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
B