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:
Which of these objects is translucent?  
 (A) A student's notebook (B) A mirror on the bus (C) A brick wall of the school (D) A student's sunglass lenses

Ex Output:
D


Ex Input:
Which physical characteristic of Earth is similar to a physical characteristic of the Moon?  
 (A) its climate (B) its great seas (C) its atmosphere (D) its mountain ranges

Ex Output:
D


Ex Input:
Students observed a turtle in the schoolyard. They measured the distance that the turtle traveled in 30 minutes. If the turtle walked 40 meters in that time, what was its average speed?  
 (A) 0.75 m/h (B) 20 m/s (C) 80 m/h (D) 1,200 m/h

Ex Output:

C