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 illness is always caused by an infection?  
 (A) a heart attack (B) a broken bone (C) influenza (D) cancer

Ex Output:
C


Ex Input:
When sodium hydroxide reacts with a copper nitrate solution, the reaction vessel needs to be kept on ice to slow down the reaction. What best describes this reaction?  
 (A) an exothermic reaction that absorbs energy (B) an exothermic reaction that releases energy (C) an endothermic reaction that absorbs energy (D) an endothermic reaction that releases energy

Ex Output:
B


Ex Input:
n 1931, Barbara McClintock discovered that genes could change position on a chromosome. In corn plants, if a certain gene was moved next to the gene that controls kernel color, the kernels in an ear of corn were various colors. Which statement best supports McClintock's discovery?     
 (A) Genes control inherited traits in organisms. (B) Corn plants can reproduce in laboratory environments. (C) Chromosomes can move around in the nucleus of a cell. (D) Genes are able to disappear and reappear in later generations.

Ex Output:

A