This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Life cycle of RBC is: \nSelect and explain. \nA. 12 days, B. 90 days, C. 120 days, D. One month', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]