Some cost related to Apple's iPad are listed below. Classify each cost as either direct materials, direct labor, factory overhead, selling expenses, or general and administrative expenses.

1. Display screen

2. Assembly line supervisor salary

3. Wages for assembly workers.

4. Salary of the Chief Executive officer

5. Glue to hold iPad cases together

6. Uniforms provided for each factory worker

7. Wages for retail store worker

8. Depreciation (straight line) on robotic equipment used in assembly