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

Ex Output:
B


Ex Input:
Organisms contribute to the water cycle mainly through the process of  
 (A) irrigation. (B) evaporation. (C) precipitation. (D) transpiration.

Ex Output:
D


Ex Input:
In order to carry out the functions of life, organisms must  
 (A) have more than one type of cell. (B) be exposed to sunlight. (C) have at least one cell. (D) be able to move.

Ex Output:

C