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.

[EX Q]: Some birds fly south in the fall and return in the spring. This is an example of  
 (A) migration (B) camouflage (C) hibernation (D) growth
[EX A]: A

[EX Q]: 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
[EX A]: B

[EX Q]: Which process causes the leaves of a plant to become larger?  
 (A) repair (B) growth (C) decomposition (D) germination
[EX A]:
B