单选题An important tablespace of your database is dropped by mistake. You use the Flashback Database feature to retrieve the tablespace. You perform the following steps to retrieve the tablespace：   1. You log on to Enterprise Manager as SYSDBA.    2. You se

An important tablespace of your database is dropped by mistake. You use the Flashback Database feature to retrieve the tablespace. You perform the following steps to retrieve the tablespace：   1. You log on to Enterprise Manager as SYSDBA.    2. You select the maintenance screen.    3. You choose Perform Recovery option on the maintenance screen.    4. You choose Whole Database in the Object Type drop-down list Perform Recovery： Type screen. 5. You choose Recover to Current Time from the Operation Type on the Perform Recovery： Type screen.    6. You provide the Host Credentials for a database user. on the Perform Recovery： Type screen.    7. You click the continue button.    An information screen appears saying that the database is unavailable. What is this information screen？（）