Based on the code shown, which query lists the number and name of all customers that are either represented by sales rep 30 or that currently have orders on file, or both?
Customer ( CustomerNum, CustomerName, Street, City, State, PostalCode, Balance, CreditLimit, RepNum )
A. SELECT CustomerNum, CustomerName, FROM Customer WHERE RepNum='30' UNION SELECT Customer.CustomerNum, CustomerName, FROM Customer ;
D. SELECT CustomerNum, CustomerName, FROM Customer WHERE RepNum='30' UNION SELECT Customer.CustomerNum, CustomerName, FROM Customer, Orders WHERE Customer.CustomerNum=Orders.CustomerNum ;
C. SELECT CustomerNum, CustomerName, FROM Customer WHERE RepNum='30' WHERE Customer.CustomerNum=Orders.CustomerNum ;
D. SELECT CustomerNum, CustomerName, FROM Customer WHERE RepNum='30' UNION SELECT Customer.CustomerNum, CustomerName, FROM Customer, Orders ;