You issue this SQL command to perform an online backup of the USER_DATA tablespace:ALTER TABLESPACE user_data BEGIN BACKUP;Next, you issue an operating system command to back up user_data01.dbf, the file that belongs to the USER_DATA tablespace. You then experience an instance failure. <br /> Which three statements are true?()<img src="https://nimg.ppkao.com/2018-08/wangjing/2018080113412129158.jpg?sign=766723fe0d76eb871bf5edae7ec90033&t=62d0ed17" />
A、A
B、B
C、C
D、D
E、E