Structure of the ORDERS Table

Structure of the ORDERS table

Structure of the CUSTOMERS table
-Which of the following queries will return the same results as the following SQL statement? SELECT

A) SELECT customer#, lastname, firstname, order#
FROM customers NATURAL JOIN orders;
B) SELECT customer#, lastname, firstname, order#
FROM customers JOIN orders USING (customer#) ;
C) SELECT c.customer#, lastname, firstname, order# FROM customers c, orders o;
D) both a and b