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.

Input: Consider Input: Which energy source is nonrenewable?  
 (A) sunlight (B) biomass (C) wind (D) fossil fuel

Output: D


Input: Consider Input: Which form of energy is found in food?  
 (A) chemical (B) electrical (C) sound (D) mechanical

Output: A


Input: Consider Input: Many birds fly south for the winter. This adaptation is called  
 (A) hibernation (B) germination (C) migration (D) communication


Output: C