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]: Sal is looking at a map of Massachusetts. He has measured the distance, in inches, from Boston to Salem on the map. He wants to know how many actual miles the inches represent. What feature of the map should he look for?  
 (A) key (B) scale (C) legend (D) compass
[EX A]: B

[EX Q]: Which item is designed to change electrical energy into heat energy?  
 (A) Alarm clock (B) Hand dryer (C) Fan (D) Telephone
[EX A]: B

[EX Q]: The mineral quartz naturally forms in various colors. Which difference in quartz formation results in the different colors?  
 (A) pressure at which the processes occurred (B) temperature at which the processes occurred (C) chemical impurities present as the processes occurred (D) amount of time passed since the processes occurred
[EX A]:
C