A(n) ____ is a unique combination of letters or numbers that identifies a specific user to Windows.

A) user name
B) administrative code
C) password
D) PIN

A user name is a unique combination of letters or numbers that identifies a specific user to Windows. It is typically used in combination with a password to confirm the user's identity when logging into the system. Administrative code, password, and PIN may also be used for identification and authentication purposes, but they are not specifically tied to a user's identity in the same way that a user name is.