Examine the following statement that is used to modify the constraint on the SALES table： SQL> ALTER TABLE SALES MODIFY CONSTRAINT pk DISABLE VALIDATE； Which three statements are true regarding the above command（）
- AThe constraint remains valid.
- BThe index on the constraint is dropped.
- CIt allows the loading of data into the table using SQL*Loader.
- DNew data conforms to the constraint， but existing data is not checked
- EIt allows the data manipulation on the table using INSERT/UPDATE/DELETE SQL statements.