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:
Which of these elements is found in the greatest amount in organisms?  
 (A) carbon (B) iron (C) lead (D) neon

Ex Output:
A


Ex Input:
To which group does an animal belong if it lays eggs and has scales and gills?  
 (A) amphibian (B) bird (C) fish (D) reptile

Ex Output:
C


Ex Input:
A gardener wants to increase the ability of garden soil to retain water. Which of these should the gardener add to the soil?  
 (A) coarse sand (B) loose gravel (C) nitrogen pellets (D) organic material

Ex Output:

D