TASK DEFINITION: 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.
PROBLEM: Four objects are on a wooden ramp. Which object is most likely to roll off the ramp if it is pushed gently?  
 (A) flat eraser (B) round ball (C) bent paper clip (D) wooden cube

SOLUTION: B

PROBLEM: Plants growing in a pond release a gas that fish need to survive. Which gas do the plants release that fish use?  
 (A) helium (B) hydrogen (C) nitrogen (D) oxygen

SOLUTION: D

PROBLEM: Which measurement is best expressed in light-years?  
 (A) the rate at which the universe is expanding (B) the distance between stars in the Milky Way (C) the time it takes for planets to complete their orbits (D) the speed at which light travels through the universe

SOLUTION:
B