Which of the following bullets leaves a visible mark which is seen by the person?

Tracer bullet is a special type of bullet that while in flight will leave a visible mark or trace which is observed by the gunner to make out the strike of the shot. The bullet resembles a ball except for the fact the rear poion of the core is filled with a chemical compound (a mixture of barium nitrate and powdered magnesium along with strontium nitrate). The flash of the propellant ignites the mixture and makes it burn during the flight of the bullet thus leaving a visible mark. The other three bullets do not leave behind a visible mark. Ref: The Essentials of Forensic Medicine and Toxicology By Dr. K. S. Narayan Reddy, 27th Edition, Pages 182-201; Textbook of Forensic Medicine and Toxicology By Nagesh Kumar Rao, 1st Edition, Pages 217-242; Textbook of Forensic Medicine and Toxicology By Krishan Vij, 5th Edition, Pages 239-240, 254.