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
Dead space is increased by all, except: 
Select and explain. 
A. Anticholinergic drugs, B. Standing, C. Hyperextension of neck, D. Endotracheal intubation
D: Endotracheal intubation
Answer: D: Endotracheal intubation 
Explanation: Endotracheal intubation