Classify the following costs as direct, indirect, or neither:

a. Indirect labor incurred
b. Factory equipment depreciation
c. Indirect materials used
d. Office equipment depreciation
e. Direct materials used
f. Insurance expired on administrative facilities
g. Direct labor incurred
h. Administrative office salaries
i. Salespersons' salaries
j. Utilities on factory building
k. Utilities on administrative facilities

Please specify each as direct, indirect, or neither