B: Data Pump can employ multiple worker processes, running in parallel, to increase job performance.
D: For export jobs, the master table records the location of database objects within a dump file set. / Export builds and maintains the master table for the duration of the job. At the end of an export job, the content of the master table is written to a file in the dump file set.
/ For import jobs, the master table is loaded from the dump file set and is used to control the sequence of operations for locating objects that need to be imported into the target database.