You are given a science question (hard-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.

A bicycle is traveling at 3 meters per second (m/s). The rider applies the brakes and stops the bicycle in 3 seconds. What is the average rate of acceleration of the bicycle during this time?  
 (A) -1 m/s^2 (B) -6 m/s^2 (C) 3 m/s^2 (D) 9 m/s^2
A

The force of an object, with a certain mass accelerating at a certain rate, can be determined by using the equation below. force = mass x acceleration Which object would have the greatest force?  
 (A) a 5-kg object accelerating at 10 m/s^2 (B) a 5-kg object accelerating at 20 m/s^2 (C) a 20-kg object accelerating at 4 m/s^2 (D) a 20-kg object accelerating at 3 m/s^2
B

Which statement is not a reason why trees would be growing at different heights in a forest?  
 (A) Some require less sunlight than others. (B) The trees were planted in different years. (C) Birds are building nests in the shorter trees. (D) The taller trees only have leaves on the top branches.

C

