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: Surgery
[{'content': 'Maximum tourniquet time for the upper limb is ? \nSelect and explain. \nA. 1/2 hour, B. 1 hr, C. 1-1/2 hrs., D. 2 hrs', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., 1-1/2 hr. In experiment animals tourniquets have been retained for three hours without lasting ill effect but in practice an hour and a half is probably a wise limit.", 'role': 'assistant'}]