On an Average Day,Tennis R Us Writes Checks Totaling $2,000

On an average day,Tennis R Us writes checks totaling $2,000. These checks take 3 days to clear. The company receives checks totaling $1,800. These checks take 2 days to clear. The cost of debt is 8%. What is the firm's collection float?

A) $-4,500
B) $-3,600
C) $3,600
D) $4,500
E) None of these.