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

A) Straight-line depreciation 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 the number of course sessions varies

F) Lumber used by a house construction company

G) The cost of operating a research department

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

I) Laser printer paper for a deparment printer

J) Electric power in a restaurant