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: Unknown
[{'content': 'The first H2 receptor blocker was synthesized in 1972 by – \nSelect and explain. \nA. Asch and Child, B. Sir James Black, C. Gaddum and Picarelli, D. Vane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sir James Black. He synthesized the first H2 blocker burimamide; and subsequently cimetidine.\nAsch and Child classified histamine receptors into H1 and H2.\nGaddum and Picarelli classified serotonin receptors into D type and M type.\nVane observed that aspirin acts by inhibiting PG synthesis.', 'role': 'assistant'}]