This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preoperative assessment and monitoring in anaesthesia, Subject name: Anaesthesia
Most common cause for end tidal CO2 falls due to 
Select and explain. 
A. Cardiac arrest, B. Extubation, C. Hypothermia, D. Hyperhermia
B: Extubation
Answer: B: Extubation 
Explanation: The most common cause for fall in EtCO2 levels is accidental extubation.