Explanation:

- Option 1: Signing

Involves validating or authorizing something, often using digital signatures. Not related to starting a device.

- Option 2: Booting

This is the correct answer. It is the process of starting up a computer or embedded device, loading the operating system, and initializing hardware components.

- Option 3: Spoofing

Refers to tricking or misleading systems by falsifying data, not related to starting a device.

- Option 4: Threading

Relates to executing multiple sequences of instructions concurrently, typically within a program.

- Option 5: Logging

Involves keeping records or logs of events. Not related to starting a device.