All of the data files must be from a backup taken prior to the point in time to which you want to recover.

Only the data files belonging from the SYSTEM tablespace must be from a backup taken prior to the point in time to which you want to recover.

Only the data files that need recovery must be from a backup taken prior to the point in time which you want to recover.

Only the data files belonging to the SYSTEM tablespace and the data files that need recovery must be from a backup taken prior to the point in time to which you want to recover.