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.

[Q]: Most of the United States is a part of which tectonic plate?  
 (A) Pacific Plate (B) Eurasian Plate (C) North American Plate (D) South American Plate
[A]: C


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


[Q]: The temperature of the stratosphere increases with altitude because of the presence of  
 (A) nitrogen. (B) water vapor. (C) ozone. (D) carbon monoxide.
[A]:
C