Which of the following key is not on the number

Which of the following is not a peripheral unit? 

What type of printers are based on the principle that a heated fluid produces bubbles or droplets?

Which of the following file extension denotes Excel Spreadsheet?

___________ is a hard copy of document.

What is two-factor authentication (2FA)?

What process involves converting a message into a secret code to ensure confidentiality?

At which layer of the OSI model do routers operate?

Where does the Sleep mode save any open documents and programs?

What is the purpose of a VPN (Virtual Private Network) in cybersecurity?

.................. is any technical effort to manipulate the normal behavior of network connections and connected systems.