a store purchased 500 in merchandise on account.using the periodic inventry system,how would you record your entry?

Question

(a)debit merchandise inventory 500 and credit accounts payable 500
(b)credit purchase 500 and debit accounts payable 500
(c)credit merchandise inventory 500
and debit accounts payable 500
(d)debit purchase 500 and credit accounts payable 500
my answer is
a