DEF Inc. purchased $20,000 of merchandise on 5/1/21, terms: 2/10, N/30. Payment was made on 5/10/21. If DEF uses the net method, which of the following would be recorded on either 5/1 or 5/10?

a) debit to purchases for $20,000 b) credit to purchase discounts for $400

c) credit to cash for $19,600 d) debit to discounts lost for $400.