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.

Input: Consider Input: Two layers of sedimentary rock are exposed on the side of a hill. Only one of the layers has fossils. The lack of fossils in one layer of sedimentary rock is most likely due to  
 (A) changing environments. (B) volcanic activity. (C) changing rates of erosion. (D) evaporation of sea water.

Output: A


Input: Consider Input: Which of the following is least likely to allow electricity to flow?  
 (A) aluminum (B) copper (C) plastic (D) water

Output: C


Input: Consider Input: As a car burns fuel, a transformation from chemical to mechanical energy takes place. What is the most likely result of the fuel burning?  
 (A) The matter that makes up the car increases. (B) The amount of useful energy decreases. (C) The efficiency of the car increases. (D) The amount of heat energy decreases.


Output: B