Below is a list of costs. Classify each of them as variable, fixed, or mixed (a combination of variable and fixed components.

a) Cost of raw materials used in producing a firm's products.

b) Property taxes.

c) Wages of sales staff paid on a salary plus commission basis.

d) Wages of hourly paid production-line workers.

e) Site licence for software.

f) Leasing costs for a delivery truck ($600 per month plus $0.40 per km.)

g) Packaging materials for products.

h) Insurance.