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]: Historically, how has the compass been used?  
 (A) for navigation (B) to predict weather (C) to measure temperature (D) for mineral identification
[EX A]: A

[EX Q]: 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
[EX A]: C

[EX Q]: The process by which water vapor in the atmosphere cools and becomes a liquid is called  
 (A) evaporation. (B) perspiration. (C) condensation. (D) transportation.
[EX A]:
C