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.

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

Ex Output:
A

Ex Input:
Which of these best describes wind energy?
(A) limited (B) renewable (C) damaging (D) inexpensive

Ex Output:
B

Ex Input:
Humans cannot survive without clean, fresh water. Reservoirs of liquid water vary, but all water spends time as a gas in the atmosphere. What is the source of most of the water in the atmosphere?
(A) lakes (B) oceans (C) rivers (D) glaciers

Ex Output:
B