TASK DEFINITION: You are given a science question (hard-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.
PROBLEM: An example of a solid turning into a liquid is  
 (A) steam turning into water. (B) water turning into steam. (C) ice turning into water. (D) water turning into ice.

SOLUTION: C

PROBLEM: Which statement is an opinion about the element copper?  
 (A) Copper is a good conductor of electricity. (B) Copper mixed with silver is expensive. (C) Copper can be pounded into many shapes. (D) Copper is an excellent conductor of heat.

SOLUTION: B

PROBLEM: Which form of water is most likely to appear when the temperature is below freezing?  
 (A) fog (B) rain (C) snow (D) clouds

SOLUTION:
C