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 are x rays and ultraviolet light?  
 (A) nuclear (B) heat (C) electromagnetic (D) chemical

Ex Output:
C


Ex Input:
Living things are classified as producers or consumers according to  
 (A) their speed of movement (B) the size of their communities (C) how they obtain food (D) how they reproduce

Ex Output:
C


Ex Input:
Which type of rock is formed when limestone is subjected to heat and pressure?   
 (A) sandstone (B) basalt (C) marble (D) granite

Ex Output:

C