Think of it like this, if you produce more units, wiIl "______ increase?"
If I produce 5 more ice creams, will inventory/materials change? Yes variable cost
Salaries and wages? No. Youre not going to get paid $12 an hour compare to $11 just because the units produced Increased. However if this just said wages, id give a different answer because it affects the labor costs, activity x wage = increase
Will you need more supplies to produce more units? Yes (direct supplies that you need to make your product)
Is advertising cost going to increase because you produce 5 extra? No
Depreciation, insurance, taxes, repairs, interest are fixed costs
Variable costs respond directly towards the change in activity
Is rent cost relative towards the production output activity or the monthly use of land.. first one so variable