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: While conducting an experiment on gravity, what will be needed to ensure the safety of students?  
 (A) quiet zones (B) drop zones (C) heavy objects (D) frictionless surfaces

A: B
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Q: The ounce, the pound, and the ton are units of  
 (A) time. (B) weight. (C) length. (D) distance.

A: B
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Q: Earthquakes and volcanic eruptions occur both on land and in water. Earthquakes and volcanic eruptions most often occur  
 (A) near plate boundaries (B) on large pieces of land (C) in large bodies of water (D) in regions near the equator

A:
A
****