Classify the following short-run manufacturing costs as either typically fixed or typically variable. Which costs are variable

Question:

Classify the following short-run manufacturing costs as either typically fixed or typically variable. Which costs are variable at management's discretion? Are any of these costs fixed in the long run?
a. Insurance
b. Direct labor
c. Bad-debt loss
d. R&D
e. Advertising
f. Raw materials
g. Depletion
h. Depreciation
i. Maintenance