This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': '16F circumference of a catheter means \nSelect and explain. \nA. 4.8 mm, B. 2.8 mm, C. 8.4 mm, D. 8.2 mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a (4.8 mm). (Ref. B & L, Surgery, 23rd ed., 1262)3.12 SF = 1mm, hence a 16F Circumference of catheter means (r)', 'role': 'assistant'}]