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