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': 'All are true about lignocaine except – \nSelect and explain. \nA. Most commonly used anesthetic agent, B. Effective for 45–60 minute, C. Safe for person prone to malignant hyperthermia, D. None', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lignocaine can precipitate malignant hyperthermia, therfore it should not be used in patients with history of malignant hyperthermia.\nLignocaine is the most commonly used anesthetic. Its duration of action is 45-60 min without adrenaline and 2-3 hours with adrenaline.', 'role': 'assistant'}]