Answer:
The correct answer to the following question will be Option C (PIN).
Step-by-step explanation:
The PIN is the failsafe system to authenticate in case the identification software is not available. This is a numeric password used only to authenticate a user who has access to the system.
The other three choices aren't in the right answer because they have not been authenticated if image recognition or any other identifying software is unavailable.
Therefore, Option C is the right answer.