Instructions: 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.
Input: Nicole was studying different ecosystems. She compared the number of plants living in a forest to those in a desert. Which factor best explains why more plants may survive in a forest?  
 (A) There is more rain in the forest. (B) There is more oxygen in the forest. (C) There is more sunlight in the forest. (D) There is more competition in the forest.
Output:
A