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.

Q: Which of the following would be more likely to pollute a river?  
 (A) allowing beavers to build a dam (B) spreading fertilizer near the river (C) mowing the grass on the river bank (D) fishing from a bridge over the river

A: B
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Q: The molecule ATP is composed of elements commonly found in organic molecules. Which of the following is one of these elements?  
 (A) aluminum (B) calcium (C) phosphorus (D) tin

A: C
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Q: Which is the best reason for planting a tree away from a sidewalk?  
 (A) The tree would get sunlight. (B) The tree would provide shelter for birds. (C) The sidewalk might crack as the tree grows. (D) The temperature of the sidewalk would drop.

A:
C
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