This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Burn), Subject name: Surgery
[{'content': 'Green coloured i.v. cannula, the size is - \nSelect and explain. \nA. 18, B. 20, C. 22, D. 24', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 18Colour coding of iv cannuleSizeColour14 gOrange16 gGrey18 gGreen20 gPink22 gBlue24 gYellow/lime", 'role': 'assistant'}]