Classify variable, fixed, or mixed cost for units produced and sold

a) Ink used for screen printing

b) Warehouse rent of $8000per month plus $0.50 per square foot of storage used

c) Thread

d) Electricity costs of $0.038 per kilowatt-hour

e) Janitorial costs of $4000 per month

f) Color dyes for producing different colors of T-shirts

g) Straight-line depreciation on sewing machines

h) Hourly wages of sewing machine operators

i) Property taxes on factory, building, and equipment

j) Maintenance costs with sewing machine company ( the cost is $2000 per year plus $0.001 for each machine hour of use)