（297）View the Exhibit for some of the parameter settings. You start a session and issue the following command:

SQL>CREATE INDEX emp_ename ON emp(ename) TABLESPACE users INVISIBLE;

What is the outcome of the above command?

A. The index is not used by the optimizer but is maintained during DML operations.

B. The index is not used by the optimizer and is not maintained during DML operations.

C. The index is used by the optimizer only if a hint is specified in the query statement and is maintained during DML operations.

D. The index is used by the optimizer only if a hint is specified in the query statement but is not maintained during DML operations.

答案：（A）