Which two statements describe data dictionary views?
A.
They are stored in the SYSTEM tablespace.
B.
They are based on virtual tables.
C.
They are owned by the SYS user.
D.
They speed up query and data manipulation language (DML) operations.
E.
The VSFIXED_TABLEview can be queried to list the names of these views.
D and E are NOT the best answers. It should be A and C.
See: Database Concepts – (6) Data Dictionary and Dynamic Performance Views
Storage of the Data Dictionary
All data dictionary tables and views for a database are stored in the SYSTEM tablespace. Because the SYSTEM tablespace is always online when the database is open, the data dictionary is always available when the database is open.
How Oracle Database Uses the Data Dictionary
The Oracle Database user SYS owns all base tables and user-accessible views of the data dictionary. Data in the base tables of the data dictionary is necessary for Oracle Database to function. Therefore, only Oracle Database should write or change data dictionary information. No Oracle Database user should ever alter rows or schema objects contained in the SYS schema because such activity can compromise data integrity. The security administrator must keep strict control of this central account.
Reference: https://docs.oracle.com/database/121/CNCPT/datadict.htm#CNCPT1210
A & C are the best answers
A , C
The data dictionary is structured in tables and views, just like other database data. All the data dictionary tables and views for a given database are stored in that database’s SYSTEM tablespace.
Oracle creates public synonyms on many data dictionary views so users can
access the views conveniently. Data dictionary is owned by user SYS.