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': 'Patient undergoing surgery was given a muscle relaxant. It produced marked fall in B.P. and increase in airway resistance which were reversed with diphenhydramine. The muscle relaxant was most probably : \nSelect and explain. \nA. Atracurium, B. Diazepam, C. Tubocurarine, D. Vecuronium', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]