In RMAN， when the RESYNC CATALOG command is issued， in which two situations does the command file actually perform synchronization？（）

A. fter the COPY command.

B. fter adding a data file in the target database.

C. fter adding a tablespace in the target database.

D. fter adding a tablespace in the catalog database.

E. fter dropping a data file in the catalog database.

F. fter running SQL Loader to load a large amount of data.