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:
When manned space exploration began, NASA used the gravity assist concept so that spacecraft could conserve fuel. Which statement explains why the gravity assist concept was useful for spacecraft to successfully travel and return to Earth?  
 (A) It gave spacecraft a timed trajectory. (B) It ensured spacecraft would return home safely. (C) It was helpful in planning spacecraft trajectories. (D) It ensured spacecraft would avoid being pulled into the sun.

Ex Output:
C


Ex Input:
Some pea plants always have peas with smooth skin. Other pea plants always have peas with wrinkled skin. How can a student best predict which kind of pea will grow from a seed that is planted?  
 (A) by checking the amount of water in the soil (B) by checking how often the pea plant receives sunlight (C) by checking how much space the plant will have to grow (D) by checking the type of peas growing on the parent plants

Ex Output:
D


Ex Input:
Which of the following describes asexual reproduction?   
 (A) the process of meiosis in a fruit fly (B) fertilization of a chicken egg (C) binary fission in an amoeba (D) the process of embryo development in a mouse

Ex Output:

C