Ruff Wear Expects Sales of $560,$650,$670,and $610 for the Months

Ruff Wear expects sales of $560,$650,$670,and $610 for the months of May through August,respectively.The firm collects 20 percent of sales in the month of sale,70 percent in the month following the month of sale,and 8 percent in the second month following the month of sale.The remaining 2 percent of sales is never collected.How much money does the firm expect to collect in the month of August?

A) $621
B) $628
C) $633
D) $639
E) $643