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.

Example Input: Which describes a material that is not a food?
(A) It stores energy but not nutrients. (B) It does not store energy or nutrients. (C) It stores energy and nutrients. (D) It does not store energy but stores nutrients.
Example Output: B

Example Input: In the human body, which system functions primarily to defend the body against disease?
(A) digestive (B) immune (C) nervous (D) respiratory
Example Output: B

Example Input: Which organism is able to work together with other cells of its species?
(A) amoeba (B) euglena (C) paramecium (D) volvox
Example Output:
D