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
Black gun powder made of: 
Select and explain. 
A. Potasium nitrate, B. Charcoal, C. Sulfur powder, D. All
D: All
Answer: D: All 
Explanation: A i.e. Potassium nitrate; B i.e. Charcoal; C i.e. Sulfur