Mr. Smith did not pay his full credit card balance on june 5th , the due date each month for payment. The unpaid balance was $800 .He purchased a new washing machine on credit on june 30th for $1000 . If interest is charged at a rate of 18% , compounded daily, what would be the interest charge on hus next credit card bill using the average daily balance method?

a) $26.63

b) 21.77

c) 14.79

d) 13.68