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: Joann repeatedly overfed the fish in the pond behind her house. The nitrates from the excess food contributed to an overgrowth of algae. To correct the problem, Joann added more plants to the pond. How will adding more plants help?  
 (A) The plants make the pond look beautiful. (B) The plants will camouflage the green algae. (C) The plants will compete with algae for nutrients. (D) The plants will provide all the food for the fish.
Example Output: C

Example Input: Kim lost her hammer outside. When she found it a few months later, some parts of the metal were covered with flaky, brown rust. Which type of change occurred when rust formed on the hammer?  
 (A) chemical (B) electrical (C) thermal (D) physical
Example Output: A

Example Input: Sand and iron particles that are similar in size and color are mixed together in a beaker. What would be the best method of separating the particles?  
 (A) Use tweezers to separate them. (B) Use a magnet to separate them. (C) Add water to the mixture. (D) Pour the mixture into a filter.
Example Output:
B