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: Manuel wants an area in the yard to wash the dog without making mud puddles. He wants to put something on the ground that water passes through easily. Which of these materials would be the best for him to use?  
 (A) clay (B) plastic (C) soil (D) pebbles
Example Output: D

Example Input: A cupful of water and a similar cupful of gasoline were placed on a table near a window on a hot sunny day. A few hours later it was observed that both the cups had less liquid in them but that there was less gasoline left than water. What does this experiment show?  
 (A) All liquids evaporate. (B) Gasoline gets hotter than water. (C) Some liquids evaporate faster than others. (D) Liquids will only evaporate in sunshine. (E) Water gets hotter than gasoline
Example Output: C

Example Input: Mrs. Gordon's class studies maple trees. Which property can the students measure with a meter stick?  
 (A) the mass of a leaf (B) the volume of its sap (C) the length of a branch (D) the temperature of its bark
Example Output:
C