Indicate whether each of the following costs of an automobile manufacturer would be classified as direct materials, direct labor, or manufacturing overhead.

a. __________ Windshield.

b. __________ Engine.

c. __________ Wages of assembly-line worker.

d. __________ Depreciation of factory machinery.

e. __________ Factory machinery lubricants.

f. __________ Tires.

g. __________ Steering wheel.

h. __________ Salary of painting supervisor.

Identify product and period costs.