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:
Oxygen reacts with iron to produce rust and with hydrogen to produce water. Which statement describes both reactions?  
 (A) A different mixture is formed in each case. (B) A different solution is formed in each case. (C) Both a change of state and of elements is involved. (D) New molecules are formed but the same elements exist.

Ex Output:
D


Ex Input:
Which statement describes animal embryos?  
 (A) display all the features of an adult (B) represent the earliest stage of development (C) have the same number of cells as a fertilized egg (D) have half the number of chromosomes as an adult

Ex Output:
B


Ex Input:
Sheri went on a field trip with her class and saw a stream with floating garbage. How could this pollution affect humans?  
 (A) There may not be enough drinking water. (B) There may not be enough water in the water cycle. (C) There may not be enough oxygen for humans to breathe.

Ex Output:

A