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
What should be the internal diameter of the endotracheal tube in a child weighing 1500 gm ? 
Select and explain. 
A. 2 mm, B. 2.5 mm, C. 3 mm, D. 3.5 mm
C: 3 mm
Answer: C: 3 mm 
Explanation: Body weight in grams and internal diameter of ET tube :-
< 1000 gm = 2.5 mm, 1000-2000 gm = 3 mm, 2000-3000 = 3.5 mm, > 3000 = 3.5-4.0 mm.