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: Dental
[{'content': 'Efficacy of a new drug A is compared with an existing drug B in : \nSelect and explain. \nA. Clinical trial phase I, B. Clinical trial phase II, C. Clinical trial phase III, D. Clinical trial phase IV', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]