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: A biological community is made up of all the  
 (A) populations living in an area (B) natural resources present in an area (C) members of a species on Earth (D) environments on Earth

Output: A


Input: Consider Input: What type of force keeps the planets orbiting the Sun?  
 (A) gravitational (B) magnetic (C) electrical (D) nuclear

Output: A


Input: Consider Input: The loudness of sound can be changed by  
 (A) decreasing the pitch. (B) increasing the frequency. (C) increasing the amplitude. (D) decreasing the wavelength.


Output: C