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.

[EX Q]: Where do good bacteria grow to help keep people healthy?
(A) in the brain (B) in the blood (C) on the skin (D) on the bones
[EX A]: C

[EX Q]: 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
[EX A]: B

[EX Q]: Four students tried to find out which magnet was the strongest. They each shared one idea. Which idea shows scientific thinking?
(A) We can pick the longest magnet. (B) We can pick the heaviest magnet. (C) We can measure the strength of the magnets. (D) We can vote for the magnet that we think is the strongest.
[EX A]:
C