Given the task definition and input, reply with output. You are given a science question (hard-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.

Which statement best describes the roles of photosynthesis and respiration in the carbon cycle?  
 (A) Respiration and photosynthesis both add carbon to the atmosphere. (B) Respiration and photosynthesis both remove carbon from the atmosphere. (C) Respiration adds carbon to the atmosphere, while photosynthesis removes carbon from the atmosphere. (D) Photosynthesis adds carbon to the atmosphere, while respiration removes carbon from the atmosphere.

C