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]: 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 unit is used to indicate the amount of energy in food?  
 (A) ounce (B) degree (C) calorie (D) gram
[EX A]: C

[EX Q]: Louisa needs to demonstrate a solution to her class. Which is the best example of a solution?  
 (A) mixing salt and pepper (B) melting butter (C) stirring salt into water (D) melting an ice cube
[EX A]:
C