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:
Vehicle exhaust contains a form of pollution called particulate matter. Technologies are being developed to reduce the amount of particulate matter in exhaust. A vehicle that produces less particulate matter would have the greatest impact on which aspect of human health?
(A) heart health (B) respiratory health (C) the rate of birth defects (D) weight and physical fitness

Ex Output:
B

Ex Input:
Prolonged exercise stimulates muscle cells to absorb sugar from the blood. This mechanism reduces stress placed on the body by signaling the body to produce
(A) insulin. (B) lipids. (C) hemoglobin. (D) hydrochloric acid.

Ex Output:
A

Ex Input:
A whistle produces a sound because blowing air in the whistle causes
(A) the whistle material to shake. (B) the air inside the whistle to vibrate. (C) the air to be absorbed by the whistle. (D) the air in the whistle to heat up and expand.

Ex Output:
B