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 Input:
When the cardboard cone of a radio speaker vibrates, it produces a sound in the air around it. The cone produces this sound by transferring which of the following to the air around it?  
 (A) heat (B) current (C) wave motion (D) magnetic force

Ex Output:
C


Ex Input:
A puppy has traits from its mother and its father. Which of these structures provides genetic information from the father to the puppy?  
 (A) a muscle cell (B) a nerve cell (C) a blood cell (D) a sperm cell

Ex Output:
D


Ex Input:
An electrical circuit can be used to break down water into hydrogen and oxygen. In this process, electrical energy produces  
 (A) kinetic energy. (B) physical changes. (C) chemical changes. (D) potential energy.

Ex Output:

C