Answer: 9mm Parabellum is correct
Some extra relevant information:
The Luger pistol, also known as the Pistole Parabellum or P08, is chambered for the 9x19mm Parabellum cartridge. This renowned semi-automatic handgun was developed by German firearms designer Georg Luger and introduced in the early 20th century. The 9x19mm Parabellum cartridge, commonly known as 9mm Luger, offers a balanced combination of manageable recoil, high muzzle velocity, and reliable performance, making it a popular choice among military, law enforcement, and civilian shooters worldwide.