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': 'Which of the following may result in sudden increase in ETCO2– \nSelect and explain. \nA. Malignant hyperthermia, B. Hyperthyrodism, C. Shivering, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Malignant hyperthermia, hypermetabolic states (hyperthyroidism) and increased skeletal muscle activity (shivering) can cause rise in ETCO2', 'role': 'assistant'}]