This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CLINICAL TRIALS, DRUG LABEL, Subject name: Pharmacology
[{'content': 'Healthy volunteers are recruited in which phase of clinical trials? \nSelect and explain. \nA. Phase 1, B. Phase 2, C. Phase 3, D. Phase 4', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Phase 1- Done on healthy people. Maximum tolerable dose of drug is tested Phase 2- Done on fewer patients (20-200) . Efficacy and safety of drug is tested here Phase 3-Done on more patients ( upto 5000).Efficacy is confirmed in this phase Phase 4- Post marketing surveillance. Long term and rare side effects are monitored in this phase', 'role': 'assistant'}]