This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Injuries, Subject name: Forensic Medicine
Choking is seen in 
Select and explain. 
A. Revolver, B. Pistol, C. Shot gun, D. Rifle
C: Shot gun
Answer: C: Shot gun 
Explanation: (C) (Shotgun) (4, 33- Parikh 6th)* Choking is the constrictive device present at the muzzle end of the shotgun.* Stallete wound may be seen in - contact wound bullet entry wound*.* Tracer bullet leaves a visible mark so that a person can see it.* Destructive power of bullet is determined by - velocity of bullet.Smokeless powderBlack powder or smoke producing powder* Single base - Nitrocellulose (Gun cotton)* Double base - Nitroglycerine plus nitrocellulose *** Triple base - Nitroglycerine, nitrocellulose and nitroguanidineConsists of* Potassium nitrate 75%* Sulphur* Charcoal10%15%One gram of powder produces 3000 to 4500 cc of gas that consists of CO, CO2 nitrogen, hydrogen sulphide, hydrogen, methane etc.* Gunpowder and/ or soot on heavily blood stained (or dark coloured) garments can be visualized by Infra red photography