You are given a science question (hard-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:
A lake has been used for more than a century to irrigate crops. How has this practice most likely affected this resource?  
 (A) It decreased the salt content of the water. (B) It increased the evaporation rate of the water. (C) It increased the number of fish in the lake. (D) It decreased the volume of the lake.

Ex Output:
D


Ex Input:
Which will most likely result from a low-pressure weather system?  
 (A) warm temperatures (B) cloudy conditions (C) clear conditions (D) cool temperatures

Ex Output:
B


Ex Input:
Which of the following actions will increase the gravitational force between two masses, m_{1} and m_{2}, by the greatest amount?  
 (A) Halve the mass of m_{1} and halve the distance between m_{1} and m_{2}. (B) Halve the mass of m_{1} and double the distance between m_{1} and m_{2}. (C) Double the mass of m_{1} and halve the distance between m_{1} and m_{2}. (D) Double the mass of m_{1} and double the distance between m_{1} and m_{2}.

Ex Output:

C