You created a profile APP_USER and assigned it to the users. After a month， you decide to drop theprofile.Some user sessions are currently connected to the database instance and are using the APP_USERprofile. This command is used to drop the profile： SQL> DROP PROFILE app_user； Which statement describes the result（）

A. The command produces an error.
B. The profile is dropped and current user sessions use the DEFAULT profile immediately.
C. The profile is dropped and only the subsequent user sessions use the DEFAULT profile.
D. The profile is dropped， the sessions are terminated， and the subsequent user sessions use theDEFAULT profile.