You issued the following command： ALTER DATABASE ENABLE BLOCK CHANGE TRACKING； What will be the result of issuing this command？（）

A.  The block change tracking feature is enabled， and the information about the system change number is written in the change tracking file.

B.  The block change tracking feature is enabled， and the information about the log sequence number is written in the change tracking file.

C.  The block change tracking feature is enabled， and the information about the blocks that are changed since the last backup is written in the change tracking file.

D.  The block change tracking feature is enabled， and the information about the locations of the datafiles and the online redo log files are written in the change tracking file.