A password represents:

A.
Something you have.

B.
Something you know.

C.
All of the choices.

D.
Something you are.

Explanation:
The canonical example of something you know is a password or pass phrase. You might
type or speak the value. A number of schemes are possible for obtaining what you know.
It might be assigned to you, or you may have picked the value yourself. Constraints may
exist regarding the form the value can take, or the alphabet from which you are allowed
to construct the value might be limited to letters only. If you forget the value, you

may not be able to authenticate yourself to the system.