Identify three situations in which you would NOT be able to drop a tablespace. （）

• A、when the tablespace is online
• B、when the tablespace has segments with data in it
• C、when the tablespace is a default permanent tablespace for the database
• D、when the tablespace contains a table that is currently being used by transactions
• E、when the tablespace contains undo data that is needed to rollback an uncommitted transaction