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.

Input: Consider Input: How does sedimentary rock form?  
 (A) sediments cool (B) sediments melt (C) sediments separate (D) sediments compress

Output: D


Input: Consider Input: The North America Nebula is named for its similarity in shape to the North American continent. It was discovered within the Milky Way by astronomer William Herschel in 1790. What was Mr. Herschel most likely observing?  
 (A) the explosion following the collapse of a star (B) a dense cluster of stars of varying magnitudes (C) meteorites as Earth passed through the tail of a comet (D) a cloud of hydrogen gas and dust where stars are born

Output: D


Input: Consider Input: What is an energy change that takes place in a light bulb?  
 (A) Chemical energy changes to light energy. (B) Chemical energy changes to heat energy. (C) Electrical energy changes to light energy. (D) Electrical energy changes to chemical energy.


Output: C