What part of a bolt-action rifle is used to open the bolt action?

The bolt handle is the correct answer because it is the specific component of a bolt-action rifle that allows the shooter to manually manipulate the bolt. By lifting and pulling the bolt handle back, the shooter can open the action, which ejects any spent cartridge, allows for the chambering of a new round, and facilitates the maintenance of the rifle. This process is crucial for the operation of a bolt-action rifle, as it relies on this manual action to load and unload ammunition.

The other components listed have different functions: the trigger is used to release the firing mechanism and discharge the round, the safety is a mechanism to prevent accidental firing, and the magazine is where ammunition is stored but does not directly facilitate the opening or closing of the bolt action. Understanding the role of each part helps clarify how a bolt-action rifle operates as a whole.