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
Endotracheal tube size in a full term infant? 
Select and explain. 
A. 2.5 mm, B. 3.5 mm, C. 4.5 mm, D. 5.5 mm
B: 3.5 mm
Answer: B: 3.5 mm 
Explanation: 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