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]: Which of these is the center of our solar system?
(A) Mars (B) The moon (C) Jupiter (D) The sun
[EX A]: D

[EX Q]: Jeannie put her soccer ball on the ground on the side of a hill. What force acted on the soccer ball to make it roll down the hill?
(A) gravity (B) electricity (C) friction (D) magnetism
[EX A]: A

[EX Q]: One unique characteristic of water is that its specific heat
(A) can only be measured in calories. (B) is lower than other common substances. (C) is higher than other common substances. (D) requires little energy for a big temperature change.
[EX A]:
C