This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthetic equipments, Subject name: Anaesthesia
[{'content': 'Which is the main component of soda-lime in closed circuit \nSelect and explain. \nA. Sodium hydroxide, B. Barium hydroxide, C. Calcium hydroxide, D. Potassium hydroxide', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sodalime constitutes a mixture of 95% Ca(OH)2, 5% NaOH and 1%KOH.', 'role': 'assistant'}]