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]: Which adaptation helps a bird fly?  
 (A) larger feet (B) bigger eyes (C) longer beaks (D) hollow bones
[EX A]: D

[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]: The Moon's surface is visible to an observer on Earth because the Moon  
 (A) reflects sunlight (B) absorbs light from Earth (C) produces its own light (D) transmits sunlight
[EX A]:
A