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: Forensic Medicine
[{'content': 'Double base smokeless gun powder contains: AIIMS 12 \nSelect and explain. \nA. Nitrocellulose and nitroguanidine, B. Potassium nitrate and sulphur, C. Potassium nitrate and charcoal, D. Nitrocellulose and nitroglycerin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. Nitrocellulose and nitroglycerin', 'role': 'assistant'}]