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 a tree suffers from a decreased ability to transport materials within the phloem, what is directly impacted?  
 (A) volume of water in the xylem (B) flow of necessary nutrients (C) response to environmental factors (D) rate of photosynthesis in leaves

Ex Output:
B


Ex Input:
Sickle cell anemia is a genetic disease caused by an autosomal recessive gene. If each parent carries one sickle cell allele, what are the chances that their child will have sickle cell anemia?  
 (A) no chance (B) one in four (C) two in four (D) three in four

Ex Output:
B


Ex Input:
In a mixture, a magnet is used to separate some particles from sand. The dark particles are most likely made of which element?  
 (A) sodium (B) iron (C) sulfur (D) copper

Ex Output:

B