[单选题]Exhibit， One of the important tables in the USERSt

A  You must recover all data files to the required system change number （SCN）.

B  You must recover all data files， except those that are offline， to the required SCN.

C  You must recover all data files belonging to the USERS tablespace to the required SCN.

D  You cannot recover all data files because segment space management is performed manually for the undo tablespace.