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
FG, FFG, FFFG is used to indicate: PGI 08, 11 
Select and explain. 
A. Caridge, B. Black powder size, C. Base of gun, D. Wadding of caridge
B: Black powder size
Answer: B: Black powder size 
Explanation: Ans. Black powder size