Cumberland Co. sells $1,001 of merchandise to Hancock Co. for cash. Cumberland paid $781 for the merchandise. Under a perpetual inventory system, which of the following is the correct journal entry(ies)?

a.debit Cash, $781; credit Sales, $781

b.debit Cash, $1,001; credit Sales, $1,001; and debit Cost of Merchandise Sold, $781; credit Merchandise Inventory, $781

c.debit Cash, $1,001; credit Merchandise Inventory, $781

d.debit Accounts Receivable, $1,001; credit Sales, $1,001; and debit Cost of Merchandise Sold, $781; credit Merchandise Inventory, $781