What does the credit terms 2/10, n/30 mean? O a. the customer can have a 2% discount if the bill is paid between the 10th and 30th day from the invoice date O b. the customer must pay the bill within 10 days O c. the customer can have a 2% discount if the bill is paid within 10 days of the invoice date O d. two sales returns can be made within 10 days of the invoice date and no returns thereafter