You are given a science question (hard-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.

Input: Consider Input: When you make soap bubbles, what is inside the bubbles?  
 (A) Air (B) Soap (C) Water (D) Nothing

Output: A


Input: Consider Input: A student gives a red toy car a push on a wooden floor. The student then pushes the same red toy car on a cement floor. Which question is the student most likely investigating?  
 (A) How fast does a toy car usually roll? (B) What is the best way to make a toy car roll? (C) Which surface allows a toy car to roll farther? (D) Does color have an effect on the distance a toy car rolls?

Output: C


Input: Consider Input: Which statement accurately describes an interaction between plants and animals?  
 (A) Plants provide humans with CO_2 for respiration. (B) Animals release CO_2, required for photosynthesis. (C) Plants provide humans with atmospheric nitrogen. (D) Animals release O_2, required for plant survival.


Output: B