Journalize the entries for the following selected transactions:

$($a$)$ Sold merchandise on account for $$12,000,$ terms $\frac{n}{30}.$ The cost of the goods sold was $$6,500.$

Sold merchandise to customers who used MasterCard

$($b$)$ and VISA, $$9,500.$ The cost of the goods sold was $$5,300.$

$($c$)$ Sold merchandise to customers who used American Express, $$2,900.$ The cost of the goods sold was $$1,700.$

Received and paid an invoice from National Clearing

$($d$)$ House Credit Co$.$ for $$460,$ representing a service fee for processing MasterCard, VISA, and American Express sales.