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 suppo ventilation (PSV), D. Assist-control ventilation (ACV)
A: Controlled mechanical ventilation (CMV)
Answer: A: Controlled mechanical ventilation (CMV) 
Explanation: Controlled Mechanical Ventilation (CMV) is best reserved for patients capable of little or no ventilator suppo. Ref: Sho Textbook of Anaesthesia By Ajay Yadav 2nd Edition, Pages 182-3.