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 describes a specific characteristic necessary for survival in the desert?  
 (A) conserving water (B) hiding from predators (C) hibernating for long periods (D) producing many offspring

Ex Output:
A


Ex Input:
Planets in the solar system are in constant motion. What factor has the greatest effect on the orbits of the planets?  
 (A) the size of the planets (B) gravitational pull of the Sun (C) the composition of the planets (D) electromagnetic radiation from the Sun

Ex Output:
B


Ex Input:
How many times does the Moon rotate on its axis during a lunar month?  
 (A) one (B) two (C) three (D) four

Ex Output:

A