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]: What property is the same for each atom of an element?  
 (A) energy (B) mass number (C) atomic number (D) number of neutrons
[EX A]: C

[EX Q]: Which is an example of a form of electrical energy?  
 (A) lightning (B) windmill (C) radio waves (D) sound waves
[EX A]: A

[EX Q]: Which animal eats only plants?  
 (A) Cat (B) Dog (C) Lion (D) Rabbit
[EX A]:
D