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: Radiology
[{'content': 'Most radioresistance phase of the cell cycle: \nSelect and explain. \nA. G1 Phase, B. G2 Phase, C. S Phase, D. M phase', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]