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?（）
- ASELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit DESC
- BSELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit
- CSELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_credit_limit NULLS LAST
- DSELECT cust_last_name, cust_credit_limit FROM customers ORDER BY cust_last_name, cust_credit_limit NULLSLAST