Classify each of the following costs as a product cost or period cost. If it is a product cost, classify it as direct (or indirect) materials, direct (or indirect) labor, or overhead.

a. Wheat used to make flour at General Mills.
b. Sales commissions paid to sales personnel at Gap retail stores.
c. Costs incurred by General Motors to ship automobile seats purchased from the Lear Corporation to GM assembly plants.
d. Insurance paid on the Target retail stores in Michigan.
e. Insurance paid on the Target warehouse holding merchandise inventory.
f. Bonus paid to all production employees of General Motors at the end of a profitable fiscal year.
g. Health care costs for the office workers at the headquarters of Johnson&Johnson Company.
h. Bolts used by Trek Bicycle Corporation to secure the bike parts to the frame.