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.

Example Input: In a copper wire, a temperature increase is the result of which of the following?  
 (A) an increase in the size of the copper particles (B) a decrease in the mass of the copper particles (C) an increase in the motion of the copper particles (D) a decrease in the distance between the copper particles
Example Output: C

Example Input: In which way is any single observation of wind speed best described?  
 (A) It is an indication of a future weather condition. (B) It is an indication of the amount of humidity. (C) It is an indication of weather at a specific time. (D) It is an indication of the existing climate.
Example Output: C

Example Input: Which of these describes the property of being a thermal insulator?  
 (A) lustrous (B) malleable (C) does not conduct heat easily (D) has a low specific heat capacity
Example Output:
C