instruction:
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.
question:
Which organ is made mostly of muscle?  
 (A) heart (B) lung (C) ear (D) brain
answer:
A


question:
Andre learned that plants survive through a process called photosynthesis. Which substance do plants produce during photosynthesis?  
 (A) minerals (B) nitrogen (C) soil (D) sugar
answer:
D


question:
Some objects are attracted by magnets. Which object is attracted by a magnet?  
 (A) an iron nail (B) an ice cube (C) a plastic knife (D) a wooden ruler
answer:

A