Code example 4-1

SELECT vendor_name, invoice_number
FROM invoices LEFT JOIN vendors
ON invoices.vendor_id = vendors.vendor_id

(Refer to code example 4-1.) The total number of rows returned by this query must equal
a. none of the above
b. the number of rows in the Invoices table
c. the number of rows in the Vendors table
d. the number of rows in the Invoices table plus
e. the number of rows in the Vendors table