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: Anaesthesia
[{'content': 'The appropriate size of LMA for an average adult patient weighing 50 kg is: \nSelect and explain. \nA. 2.5, B. 3, C. 4, D. 5', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c. 4.0', 'role': 'assistant'}]