This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ballistics, Subject name: Forensic Medicine
Name the test and is used for 
Select and explain. 
A. Neutron activation analysis for firearm use, B. Lie test for Firearm injury, C. Benzidene test for blood stain, D. Toludene blue test
A: Neutron activation analysis for firearm use
Answer: A: Neutron activation analysis for firearm use 
Explanation: Neutron activation analysis (NAA) : This is a test used for estimation of distance of firing and confirming the hands of those suspected of firing a firearm. The test can detect barium, copper, antimony, etc. from the primer present in the firearm discharge residue, which are activated in a nuclear reactor and then identified by the gamma ray spectrometer. Other tests are: * Dermal nitrate test* Harrison and gilroy test* Neutron activation analysis (NAA)* Image analysis of gunshot residue (IA GSR)* Sodium rhodizonate test