Your company requires remote system administrators to authenticate using a method more secure than passwords alone when accessing critical Linux servers. Which of the following options provides an additional layer of security that requires something the user has, in addition to something the user knows?
Using a one-time password (OTP) token in conjunction with their user password
Requiring administrators to connect using SSH keys
Implementing a strict password strength and rotation policy
Employing biometric authentication such as fingerprint or facial recognition