You need to generate a list of all customer last names with their credit limits from the CUSTOMERS table. Those customers who do not have a credit limit should appear last in the list. Which two queries would achieve the required result?（）

• A、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit DESC
• B、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit
• C、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit NULLS LAST
• D、SELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_last_name, cust_credit_limit NULLSLAST