On June $1,$ Aaron Company purchased equipment at a cost of $$120,000$ that has a depreciable cost of $$90,000$ and an estimated useful life of $3$ years and $30,000$ hours, which ends on December $31.$

Using straight$-$line depreciation, compute depreciation expense for the final $($partial$)$ year of service.

a$.$ $$17,500$

b$.$ $$12,500$

c$.$ $$40,000$

d$.$ $$30,000$