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: Consider Input: Lichens are symbiotic organisms made of green algae and fungi. What do the green algae supply to the fungi in this symbiotic relationship?  
 (A) carbon dioxide (B) food (C) protection (D) water

Output: B


Input: Consider Input: In gym class a student kicks a soccer ball high into the air. As the ball goes upward, which type of energy is increasing?  
 (A) kinetic energy (B) thermal energy (C) potential energy (D) mechanical energy

Output: C


Input: Consider Input: What causes sound?  
 (A) sunlight (B) vibrations (C) x-rays (D) pitch


Output: B