Selected costs related to Apple's iPhone are listed below.

Classify each cost as either direct materials, direct labor, factory overhead, selling expenses, or general and administrative expenses.

$\backslash$table$[[1.$ Display screen,$],[2.$ Assembly$-$line supervisor salary,$],[3.$ Wages for assembly workers,$],[4.$ Salary of chief executive officer,$],[5.$ Glue to hold iPhone cases together,$],[6.$ Uniforms provided for each factory worker,$],[7.$ Wages for retail store salesperson,$],[8.$ Depreciation $($straight$-$line$)$ on robotic equipment used in assembly,$]]$