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 Q]: Animals get energy for growth and repair from  
 (A) soil (B) food (C) water (D) air
[EX A]: B

[EX Q]: The greatest amount of diversity can be found among which type of organism?  
 (A) plants (B) animals (C) bacteria (D) fungi
[EX A]: C

[EX Q]: Which two body systems are involved in inhaling oxygen and exhaling carbon dioxide?  
 (A) endocrine and skeletal (B) excretory and nervous (C) circulatory and respiratory (D) digestive and reproductive
[EX A]:
C