A network administrator has a separate user account with rights to the domain administrator group. However, they cannot remember the password to this account and are not able to login to the server when needed. Which of the following is MOST accurate in describing the type of issue the administrator is experiencing?
A. Single sign-on B. Authorization C. Access control D. Authentication
Answer: D
Explanation: Authentication generally requires one or more of the following: Something you know: a password, code, PIN, combination, or secret phrase. Something you have: a smart card, token device, or key. Something you are: a fingerprint, a retina scan, or voice recognition; often referred to as biometrics, discussed later in this chapter. Somewhere you are: a physical or logical location. Something you do: typing rhythm, a secret handshake, or a private knock.