Sherri is reviewing her Web site for potential problems and bugs using her browser. She deletes the last directory listed in the current URL and presses ENTER. The browser immediately takes her back one level in the server directory. The Web page now reveals sensitive executable files. What has Sherri overlooked in her design process?

A.
She has not disabled the FTP hook.

B.
She has not encrypted her virtual directories.

C.
She has not enabled user authentication for directory FTP service.

D.
She has not disabled directory browsing.