You have not configured Oracle Managed Files (OMF) in your database. You do not want to scan the entire datafile every time an incremental backup is performed. You decide to enable the block change tracking feature. Which statement will you use to enable the block change tracking feature?()
A: ALTER SYSTEM ENABLE BLOCK CHANGE TRACKING;
B: ALTER DATABASE ENABLE BLOCK CHANGE TRACKING;
C: ALTER SYSTEM ENABLE BLOCK CHANGE TRACKING USING FILE 
D: ALTER DATABASE ENABLE BLOCK CHANGE TRACKING USING FILE 

出自:Oracle认证