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: Pharmacology
[{'content': 'Phase 4 clinical trial is also known as: \nSelect and explain. \nA. Human pharmacology and safety, B. Post marketing surveillance, C. Therapeutic exploration and dose ranging, D. Therapeutic conﬁrmation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]