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.

Example Input: During a walk in the woods, Mandy finds a plant structure that had fallen onto the trail. Mandy can tell the object contained seeds, and thinks it came from a flowering plant instead of a conifer. How can she determine if the object came from a flowering plant?  
 (A) by looking for seed coats on the seeds (B) by looking for wing-like structures on the seeds (C) by looking for fruit tissue around the seeds (D) by looking for young sporophytes inside the seeds
Example Output: C

Example Input: Humans use both renewable and nonrenewable resources. Which human activity uses a nonrenewable resource?  
 (A) building houses with wood (B) using natural gas to heat homes (C) using solar energy to power lights (D) producing electricity from flowing water
Example Output: B

Example Input: A unicellular organism is best described as being  
 (A) a complex organism. (B) a microorganism. (C) an organism with specialized cells. (D) an organism with different types of tissues.
Example Output:
B