A user enters a username and a password at the login screen for a web portal. A few seconds later the following message appears on the screen: Please use a comb...

A user enters a username and a password at the login screen for a web portal. A few seconds later the following message appears on the screen:
Please use a combination of numbers, special characters, and letters in the password field.
Which of the following concepts does this message describe?

A. Password complexity B. Password reuse C. Password history D. Password age