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 was invented by Benjamin Franklin?  
 (A) bifocal lens (B) telescope lens (C) telephone (D) camera

A: A
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Q: A student tosses a ball into the air. Which force causes the ball to fall back to the ground?  
 (A) gravity (B) magnetism (C) mechanical (D) friction

A: A
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Q: Which explains the pattern of day and night?  
 (A) Earth orbits the sun. (B) Earth spins on its axis. (C) The sun only transmits light energy during the daytime. (D) The sun only transmits light energy above the equator.

A:
B
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