This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'Catgut is preserved in \nSelect and explain. \nA. Glutraldehyde, B. Isopropyle alcohol, C. Iodine, D. Cetrimide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The catgut suture is supplied sterile in "pre-cut" lengths or non-needled or attached to various needle in packing fluid containing: o 90% Isopropyl Alcohol, o 0.5% Sodium Benzoate, o 0.5% Diethylethanolamine and o water q.s. ad 100%.', 'role': 'assistant'}]