You have created a locally managed tablespace by issuing the following command：        CREATE TABLESPACE data1   DATAFILE ’data1_file1.dbf’ SIZE 10M AUTOEXTEND ON MAXSIZE        UNLIMITED；   For the DATA1 tablespace， you have set the warning level alert limit to 70 percent.  In which situation will a warning level alert be generated？（）  

• A、 when 700 KB is used
• B、 when 700 KB is left as free space
• C、 when 7MB is used
• D、 when 7MB is left as free space
• E、 no alert will be generated because an autoextensible datafile is included in the tablespace