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: At what time on a sunny day will the shadow of the school's flagpole be the shortest?  
 (A) sunrise (B) noon (C) mid-afternoon (D) sunset
Example Output: B

Example 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
Example Output: B

Example Input: Frogs lay eggs that develop into tadpoles and then into adult frogs. This sequence of changes is an example of how living things  
 (A) go through a life cycle (B) form a food web (C) act as a source of food (D) affect other parts of the ecosystem
Example Output:
A