Not A: Both indexes are created fine.
B: The invisible index ORD_CUSTOMERS_IX1 and the bitmap index are both updated by DML operations on the Orders table.
F: Since ORD_CUSTOMERS_IX1 is invisible only ORD_CUSTOMERS_IX2 is used by the query optimizer.
Not C, Not D, Not E:
* ord_customer_ix1 is an invisible index and is therefore not used by the optimizer.
* VISIBLE | INVISIBLE Use this clause to specify whether the index is visible or invisible to the optimizer. An invisible index is maintained by DML operations, but it is not be used by the optimizer during queries unless you explicitly set the parameter OPTIMIZER_USE_INVISIBLE_INDEXES to TRUE at the session or system level.
Note: Specify BITMAP to indicate that index is to be created with a bitmap for each distinct key, rather than indexing each row separately. Bitmap indexes store the rowids associated with a key value as a bitmap. Each bit in the bitmap corresponds to a possible rowid. If the bit is set, then it means that the row with the corresponding rowid contains the key value. The internal representation of bitmaps is best suited for applications with low levels of concurrent transactions, such as data warehousing.

C: Setting the CONTROL_MANAGEMENT_PACK_ACCESS initialization parameter to DIAGNOSTIC+TUNING (default) enables monitoring of database operations. Real-Time SQL Monitoring is a feature of the Oracle Database Tuning Pack.
Note:
* The DBMS_SQL_MONITOR package provides information about Real-time SQL Monitoring and
Real-time Database Operation Monitoring.
*(not B) BEGIN_OPERATION Function
starts a composite database operation in the current session.
/ (E) FORCE_TRACKING - forces the composite database operation to be tracked when the operation starts. You can also use the string variable 'Y'.
/ (not A) NO_FORCE_TRACKING - the operation will be tracked only when it has consumed at least 5 seconds of CPU or I/O time. You can also use the string variable 'N'.

Explanation
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.