TASK DEFINITION: You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
PROBLEM: Which of the following compounds is most likely to be part of living organisms?  
 (A) C?H??O? (B) BF? (C) MoCl? (D) CsI

SOLUTION: A

PROBLEM: Which of the following climates has cold winters and hot summers?  
 (A) polar (B) subtropical (C) temperate (D) tropical

SOLUTION: C

PROBLEM: If you bounce a rubber ball on the floor, it goes up and then comes down. What causes the ball to come down?  
 (A) magnetism (B) gravity (C) electricity (D) friction

SOLUTION:
B