This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: RCT, Trials, Subject name: Social & Preventive Medicine
[{'content': 'Maximum tolerated dose of a new drug is evaluated in: \nSelect and explain. \nA. Phase 1, B. Phase 2, C. Phase 3, D. Phase 4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Phase 1 clinical trial: Used to evaluate Maximum tolerated dose (MTD) of a new drug. Healthy human volunteers are used. Done for safety and non-toxicity.', 'role': 'assistant'}]