Indicate whether each item listed below is a variable (V), fixed (F), or mixed (M) cost and whether it is a product or service (PT) cost or a period (PD) cost. If some items have alternative answers, indicate the alternatives and the reasons for them.
a. Wages of forklift operators who move finished goods from a central warehouse to the loading dock.
b. Paper towels used in factory restrooms.
c. Insurance premiums paid on the headquarters of a manufacturing company.
d. Columnar paper used in an accounting firm.
e. Cost of labels attached to shirts made by a company.
f. Wages of factory maintenance workers.
g. Property taxes on a manufacturing plant.
h. Salaries of secretaries in a law firm.
i. Freight costs of acquiring raw materials from suppliers.
j. Cost of wax to make candles.
k. Cost of radioactive material used to generate power in a nuclear power plant.