Each rifle or handgun is designed to be used with which specific component?

The correct answer is that each rifle or handgun is designed to be used with a specific cartridge. A cartridge is a complete package that includes the projectile (bullet), the casing, primer, and gunpowder. Each firearm is manufactured to work with particular specifications of cartridges, including caliber and pressure, ensuring safe and efficient operation. Using a cartridge that does not match the firearm can lead to malfunctions, misfires, or even catastrophic failures.

The other components mentioned, such as a magazine, trigger mechanism, and stock, while integral to the overall function and handling of the firearm, are not exclusive or specific to each model of rifle or handgun in the same way that a cartridge is. A magazine can often be interchangeable among different firearms of a similar caliber, and trigger mechanisms and stocks can be modified or upgraded without changing the firearm's fundamental operation. However, each firearm will only safely and effectively operate with its designated cartridges.