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 organ is made mostly of muscle?
(A) heart (B) lung (C) ear (D) brain

Output: A

Input: Consider Input: A student has just completed a laboratory activity. What is the last action that the student should perform before leaving the lab area?
(A) wash hands (B) turn off all equipment (C) put away all glassware (D) wash instruments and table tops

Output: A

Input: Consider Input: When a cold front moves over a land region that has warm, moist air, a transfer of energy occurs. Cold air sinks and pushes warmer air upward. As energy is removed from the air, which change will most likely take place?
(A) Ozone in the atmosphere will decrease. (B) Less ultraviolet radiation will reach the land. (C) More water will be absorbed from the area lakes. (D) Water in the atmosphere will undergo a phase change.
Output: D