This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Airway, Subject name: Anaesthesia
[{'content': 'Endotracheal tube size in a full term infant? \nSelect and explain. \nA. 2.5 mm, B. 3.5 mm, C. 4.5 mm, D. 5.5 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Age Internal Diameter (mm) Cut length (cm) Full- term infant 3.5 12 Child 4+Age/4 12+Age/2 Adult Female 7.0-7.5 24 Male 7.5-9.0 24', 'role': 'assistant'}]