Classify the total costs of each of the following as variable, fixed, mixed, or step:

A - Straight line deprectiate on a building

B - Maintenance costs at a hospital

C - Rent on a photocopy machine charged as a fixed amount per month plus an additional charge per copy

D - Cost of goods sold in a bookstore

E - Salaries paid to temporary instructors in a college as athe number of course sessions varies

F - Lumber used by a house consturction company

G - The costs of operating a research department

H - The cost of hiring a dance band for three hours

I - Laser printer paper for a department printer

J - Electric power in a restaurant