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:
Adaptive characteristics that help dolphins survive life in the ocean include all of these except  
 (A) their sleek skin. (B) swimming very fast. (C) their body shape. (D) traveling alone.

Ex Output:
D


Ex Input:
Which is true about the Sun and Earth?  
 (A) Earth gives light and heat energy to the Sun. (B) Earth gives only heat energy to the Sun. (C) The Sun gives light and heat energy to Earth. (D) The Sun gives only light energy to Earth.

Ex Output:
C


Ex Input:
Margaret is running a full lap around a circular track. She is facing north when she starts. What direction will she be facing after she has completed half of a lap?  
 (A) north (B) south (C) east (D) west

Ex Output:

B