This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Forensic Medicine
Composition of primer is 
Select and explain. 
A. Lead peroxide, B. Lead tetrazine, C. Barium nitrate, D. All of above
D: All of above
Answer: D: All of above 
Explanation: The primers are composed of lead styphnate, barium nitrate and antimony sulphide. Most centrefire primers are composed of all the three compounds. The detection of these compounds constitutes the basis for the tests to determine whether an individual has fired a firearm. In case of rimfire ammunition, the primer composition is spun into the rim of the caridge case with the propellant in intimate contact with this composition. On firing, the firing pin strikes the rim of the caridge case, compressing the primer composition and initiating its detonation Ref : Krishnan vij Textbook of Forensic medicine and Toxicology 5th edtion ; pg no - 237