A mail order house uses 18,000 boxes a year. Carrying costs are 60 cents per box a year, and ordering costs are $96. The table below shows the quantity discount ranges available to the company. If the company takes advantage of quantity discount, what would be the order size for minimum total cost?

Number of boxes | Price per box

                        1,000 to 1,999 | $ 1.25

                        2,000 to 4,999 | 1.20

                        5,000 to 9,999 | 1.15

                        10,000 or more | 1.10

A. 2,400 boxes

B. 1,000 boxes

C. 5,000 boxes

D. 10,000 boxes