What mechanism releases the slide to go forward after the last shot is fired?

The mechanism that releases the slide to go forward after the last shot is fired is the slide latch or slide release. When the last round is fired from the magazine, the slide moves to the rear and is held in that position by the slide latch. This feature allows the shooter to know that the firearm is empty and needs to be reloaded.

Once a new magazine is inserted and the shooter activates the slide release, either by pressing down on it or letting the slide move forward under spring tension, the slide will return to its forward position, chambering a new round from the magazine. This process is essential for ensuring that the firearm is ready to fire again after the last round has been discharged.

The other options do not serve this purpose. The hammer is part of the firing mechanism and does not affect the slide's position after firing. The trigger is what initiates the firing sequence, and the safety is a mechanism designed to prevent accidental discharge, but it does not influence the slide's movement after the last round. Thus, the slide latch or release is specifically designed to control the slide’s operation after the last shot, making it the correct answer.