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:
Compared to Earth, the Moon is  
 (A) drier. (B) larger. (C) heavier. (D) brighter.

Ex Output:
A


Ex Input:
Which series correctly represents the levels of organization in an organism?  
 (A) cells -> organs -> organ system -> tissue (B) cells -> tissue -> organs -> organ system (C) tissue -> cells -> organ system -> organs (D) tissue -> organ system -> cells -> organs

Ex Output:
B


Ex Input:
In a recycling program, people can separate paper from their other trash. The paper is sent to factories and turned into new products. What does paper recycling help conserve the most?  
 (A) air (B) gasoline (C) trees (D) water

Ex Output:

C