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: A geologist finds a layer of shale near the surface from a certain time period. Nearby, the geologist finds the same layer of shale, but it is deeper underground than the first layer. What might have caused the difference in the depth of the shale layer?
(A) a meteorite (B) a fault (C) ancient fossils (D) animal life

Output: B

Input: Consider Input: Two atoms of oxygen combine to form pure oxygen gas. What is the electrical charge of the O_{2} molecules?
(A) positive (B) negative (C) neutral (D) variable

Output: C

Input: Consider Input: The oil used today is made from the ancient remains of tiny sea creatures called "Diatoms." When they were alive, the Diatoms converted sunlight into stored energy. Based on this information, which of the following statements is true?
(A) The Sun turned diatoms into oil after 10-20 years. (B) Diatoms are the original source of energy for oil. (C) The Sun is the original source of energy for oil. (D) Diatoms converted oil into energy.
Output: C