For apparel manufacturer Abercrombie & Fitch, Inc., classify each of the following costs as either a product cost or a period cost:
a. Research and development costs
b. Depreciation on sewing machines
c. Fabric used during production
d. Depreciation on office equipment
e. Advertising expenses
f. Repairs and maintenance costs for sewing machines
g. Salary of production quality control supervisor
h. Utility costs for office building
i. Sales commissions
j. Salaries of distribution center personnel
k. Wages of sewing machine operators
l. Factory janitorial supplies
m. Chief financial officer’s salary
n. Travel costs of media relations employees
o. Factory supervisors’ salaries
p. Oil used to lubricate sewing machines
q. Property taxes on factory building and equipment