instruction:
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.
question:
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
answer:
A


question:
Which is the best example of something that has kinetic energy?  
 (A) a rock sitting at the top of a steep hill (B) a tennis ball rolling across the court (C) a picture hanging on the wall (D) a piece of wood before it is burned
answer:
B


question:
Which pieces of equipment would be used to measure the density of a solution?  
 (A) a ruler and a protractor (B) a magnet and a thermometer (C) a graduated cylinder and a balance (D) an Erlenmeyer flask and a Bunsen burner
answer:

C