Exhibit： View the Exhibit to see the data in the emp table.  You created a PRIMARY KEY constraint on the empno column of the emp table， and the constraint is not deferred. Which two statements are true in this scenario？ （）

• A、No index would be created or used in this case.
• B、A unique index on the empno column would be created.
• C、A CHECK constraint would be enforced on the empno column.
• D、A NOT NULL constraint would be enforced on the empno column.
• E、A bitmap unique index would be created on the empno column.