Perdue Company purchased equipment on April $1$ for $$35,100.$ The equipment was expected to have a useful life of $3$ years, or $3,780$ operating hours, and a residual value of $$1,080.$ The equipment was used for $700$ hours during Year $1,1,300$ hours in Year $2,1,100$ hours in Year $3,$ and $680$ hours in Year $4.$

a$.$ straight$-$line method

b$.$ units$-$of$-$activity method

c$.$ double$-$decling$-$balance method