The Payroll Department provides services for several plants in the city of Yee Haw Junction. The Payroll Department's budget is $100,000, and it issues 4,000 checks every other week. The lighting plant has 1,000 employees. How much should the lighting plant be charged by the Payroll Department for its services?
a. $4,000
b. $20,000
c. $25,000
d. Not enough information is given.