Answer 15

Correct answer: d

Explanation:

Dropping a table removes all the associated objects including indexes. To get rid of an index associated with a constraint, action has to be taken on the table or constraint, and not on the index.

The DROP INDEX drops an index in your own schema, and not any index unless you have the DROP ANY INDEX system privilege. Thus, choice A is incorrect.

The ALTER TABLE DROP CONSTRAINT works for indexes associated with unique constraints, while ALTER TABLE DROP PRIMARY KEY CASCADE works for indexes associated with PK. Thus, choices B and C are incorrect.