An electrical or mechanical device is made to work the trigger of a semi-automatic firearm. It makes the firearm fire in rapid succession. What is it?

1. 1A restricted device.
2. 2A non-restricted accessory.
3. 3A restricted firearm.
4. 4A prohibited device.

Source: Regulations Prescribing Certain Firearms and Other Weapons, Components and Parts of Weapons, Accessories, Cartridge Magazines, Ammunition and Projectiles as Prohibited, Restricted or Non-Restricted (SOR/98-462), s. 5, Part 4 of the schedule