What does a credit policy of "2/10, net 30" mean?

What does a credit policy of "2/10, net 30" mean?
A) That if the buyer pays the net bill within 10 days, a 2 percent discount will be given.
B) That the selling company offers a 2 percent discount if the customer pays within 10 days. The customer has 30 days to pay the regular price.
C) That the selling company offers a 10 percent discount if the customer pays within 2 days. The customer has 30 days to pay the regular price.
D) That the buyer has two months to pay the bill. If the buyer pays before that time, a 10 percent discount will be given.
E) None of these are correct.