Which of the following is NOT a security feature relating to user accounts？（）

A、Some commands can be password protected requiring logged in customers to re-enter their password.

B、A user account can be disabled automatically， after a specified number of invalid login attempts.

C、An account can have multiple valid passwords at the same time， any of which can be used to access the account.

D、The password policy feature can allow the system to require passwords to include a minimum number of numeric characters.

E、Logged in customers can be logged off of the system after a specified period of inactivity.