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': 'Ketanserin is : \nSelect and explain. \nA. 5HT1B antagonist, B. 5HT2 antagonist, C. 5HT1A agonist, D. 5HT1D antagonist', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]