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:
Which action involving a pulley system requires the least amount of force?  
 (A) using several pulleys together instead of a single pulley (B) using a fixed pulley instead of a moveable pulley (C) pulling a long rope instead of a short rope (D) pulling a rope up instead of down

Ex Output:
A


Ex Input:
Carlos was playing on a slide on a sunny summer day. Which property of the slide tells Carlos how much energy the slide absorbed from the Sun?  
 (A) the mass (B) the color (C) the height (D) the temperature

Ex Output:
D


Ex Input:
Grooves running down the sides of a riverbank are most likely caused by  
 (A) wind. (B) rocks. (C) leaves. (D) rainwater.

Ex Output:

D