CREATE TABLE dept (deptno NUMBER(2), dname VARCNAR2(14), 1oc VARCNAR2 (13)); ROLLBACK; DESCRIBE DEPT What is true about the set? （）

• A、The DESCRIBE DEPT statement displays the structure of the DEPT table.
• B、The ROLLBACK statement frees the storage space occupies by the DEPT table.
• C、The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist.
• D、The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.