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]: Two identical books are on opposite ends of a table. Which of these would increase the gravitational force exerted between the two books?  
 (A) decrease the distance between the books (B) decrease the mass of the books (C) decrease the mass of the table (D) decrease the temperature in the room
[EX A]: A

[EX Q]: One advantage of a hand lens over a microscope is that the hand lens  
 (A) is easier to carry on field investigations. (B) is less likely to be infected by bacteria. (C) makes very tiny objects appear larger. (D) produces a more accurate image.
[EX A]: A

[EX Q]: The systems of the human body work together. Which system works with the skeletal system by pulling on the bones to create movement?  
 (A) digestive (B) circulatory (C) muscular (D) nervous
[EX A]:
C