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
The following modes of ventilation may be used for weaning off patients from mechanical ventilation except – 
Select and explain. 
A. Controlled mechanical ventilation (CMV), B. Synchronized intermittent mandatory ventilation (SIMV), C. Pressure support ventilation (PSV), D. Assist–control ventilation (ACV)
A: Controlled mechanical ventilation (CMV)
Answer: A: Controlled mechanical ventilation (CMV) 
Explanation: It is possible to wean patient in any mode of ventilation except control mode ventilation.