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:
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 Output:
A


Ex Input:
A hearing aid is a small device that contains an amplifier, a battery, a microphone, and a speaker. Which part of a hearing aid functions to detect sounds in the user's environment?  
 (A) the amplifier (B) the battery (C) the microphone (D) the speaker

Ex Output:
C


Ex Input:
A student provides the following directions for brushing teeth: • Turn on the water. • Fill the glass with water and leave the water running. • Put toothpaste on the toothbrush. • Brush for two minutes. • Rinse mouth with the water from the glass. • Rinse the toothbrush with the running water. • Turn off the water. Which change in these directions would conserve the most water?  
 (A) Brush for three minutes. (B) Turn the water off before brushing. (C) Rinse mouth with the running water. (D) Use less toothpaste on the toothbrush.

Ex Output:

B