Freer Co. purchased a piece of machinery for $50,000. Freer will use the machinery in the production of its product line for five years, at which time the machinery will have a residual value of $5,000. Freer anticipates that it will produce 90,000 units the first year with total units of 450,000. Which of the following methods will allow Freer to claim the greatest amount of depreciation in the first year?

Sum-of-the-years' digits.

Double declining balance.

Units of production.

Straight-line.