Cassie Corporation, which uses a perpetual inventory system, purchased on account $2,000 of merchandise on July 5. Credit terms were 2/10, n/30. It returned $400 of the merchandise on July 9. When it pays its bill on July 11, the journal entry will require a:
a. debit to Accounts Payable for $2,000.
b. debit to Accounts Payable for $1,600.
c. credit to Cash for $1,600.
d. debit to Merchandise Inventory for $32.