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:
Planting certain crop plants in a field causes a disruption of the natural nitrogen cycle in that field. Which outcome would this disruption most DIRECTLY cause in the field over time?  
 (A) topsoil erodes (B) soil nutrients decrease (C) desert conditions appear (D) atmospheric carbon dioxide increases

Ex Output:
B


Ex Input:
Which of the following is closest to the percentage of the total water on earth that is freshwater?  
 (A) 100% (B) 90% (C) 70% (D) 3%

Ex Output:
D


Ex Input:
Water is a very important part of the physical weathering of rock. Which of these properties of water is most important in causing some of the physical weathering of rock?  
 (A) Water is a liquid at room temperature. (B) Water can contain different minerals. (C) Water expands when it freezes. (D) Water dissolves many chemicals.

Ex Output:

C