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:
The transfer of heat in the atmosphere by winds that circulate between the equator and the poles is an example of  
 (A) radiation. (B) insulation. (C) convection. (D) conduction.

Ex Output:
C


Ex Input:
An object such as a hammer weighs less on the Moon than on Earth. This is because the Moon has a  
 (A) thinner atmosphere than Earth. (B) smaller diameter than Earth. (C) stronger magnetic field than Earth. (D) lower mass than Earth.

Ex Output:
D


Ex Input:
The human hearing range is 20-20,000 hertz. A sound Peggy heard was measured at 15,000 hertz. Which characteristic best describes the sound wave that Peggy heard?  
 (A) fast speed (B) high frequency (C) large amplitude (D) long wavelength

Ex Output:

B