why is it wrong? please provide steps

The following transactions entered by a company during May 2019: 2019 May. 1 Sold merchandise on account to a customer for $18,000, terms 2/15/30. May. 5 The customer returned merchandise worth $1,000. May. 9 Received payment in full from the customer On May 9, the Sales Discount account should be: O a. credited by 360 b. debited by 360 x O c. credited by 340 d. There is not any Sales Discount to be recorded e. debited by 340