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
[{'content': 'The following modes of ventilation may be used for weaning off patients from mechanical ventilation, EXCEPT: \nSelect and explain. \nA. Controlled mechanical ventilation (CMV), B. Synchronized intermittent mandatory ventilation (SIMV), C. Pressure suppo ventilation (PSV), D. Assist-control ventilation (ACV)', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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.', 'role': 'assistant'}]