What Do Credit Terms of 2/10,n/30 Indicate

What do credit terms of 2/10,n/30 indicate?

A) two percent discount for early payment is available if the invoice is paid before the tenth day of the month following the month the sale.
B) two percent discount for early payment is available within ten days of the invoice date.
C) ten percent discount for early payment is available if the invoice is paid within two days of the date of the invoice.
D) two percent discount for early payment is available if the invoice is paid after the tenth day,but before the thirtieth day of the invoice date.