Consider the following statement:

Which indexes should be created for optimal query performance?

A.
CREATE INDEX emp_idx ON employee (workdept);
CREATE INDEX dept_idx ON department (deptno);

B.
CREATE INDEX emp_idx ON employee (workdept) CLUSTER;
CREATE INDEX dept_idx ON department (deptname, deptno);

C.
CREATE INDEX emp_idx ON employee (workdept, lastname, job);
CREATE INDEX dept_idx ON department (deptname, deptno);

D.
CREATE INDEX emp_idx ON employee (lastname, job, workdept) CLUSTER;
CREATE INDEX dept_idx ON department (deptname);

Explanation: