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: Social & Preventive Medicine
[{'content': 'Which phase of clinical trial involves normal human Volunteers: March 2010 \nSelect and explain. \nA. Phase 0, B. Phase I, C. Phase II, D. Phase III', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Phase I', 'role': 'assistant'}]