Evaluate these two SQL statements: SELECT last_name, salary , hire_date FROM EMPLOYEES ORDER BY salary DESC; SELECT last_name, salary, hire_date FROM EMPLOYEES ORDER BY 2 DESC; What is true about them?（）

• A、The two statements produce identical results.
• B、The second statement returns a syntax error.
• C、There is no need to specify DESC because the results are sorted in descending order by default.
• D、The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.