Cardinal Industries purchased a generator that cost $$13,000.$ It has an estimated life of $4$ years and a residual value of $$5,000.$ It is estimated to be good for $5,000$ hours. Compute the depreciation expense for the first year using the units$-$of$-$activity method of depreciation if the generator was used for $1,080$ hours.

a$.$ $$1,728$

b $$1728$

c$.$ $$2,808$

d$.$ $$8,000$