This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ballistics, Subject name: Forensic Medicine
[{'content': 'All are components of gun-powder EXCEPT: \nSelect and explain. \nA. Charcoal, B. Lead peroxide, C. Potassium nitrate, D. Sulphur', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gun Powder is of two types: a) Black gun powder: Contains Potassium nitrate 75% + Charcoal 15% + sulphur 10% b) Smokeless Powder is of following types: -Single Base: Contains nitrocellulose -Double Base: contains nitrocellulose + nitroglycerine -Triple Base: Contains Nitrocellulose + Nitroglycerine + nitroguanidine', 'role': 'assistant'}]