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.

Example Input: When the cardboard cone of a radio speaker vibrates, it produces a sound in the air around it. The cone produces this sound by transferring which of the following to the air around it?  
 (A) heat (B) current (C) wave motion (D) magnetic force
Example Output: C

Example Input: What procedure should be performed after any handling of a plant sample in a lab?  
 (A) applying disinfectant to the counters (B) throwing away plant material in the trash (C) washing hands with an antibacterial soap (D) placing hands under an ultraviolet light
Example Output: C

Example Input: Vibrations in the air caused by hitting a drum form  
 (A) radiation. (B) light. (C) electricity. (D) sound.
Example Output:
D