Wexford Co$.$ purchased a new delivery truck at the beginning of $2017.$ The truck has a cost of $$37,000,$ an estimated life of five years, and an estimated residual value of $$7,000.$ A full year's depreciation expense is to be recorded in $2017.$ The truck was driven $20,000$ miles during $2017$ and $24,000$ miles during $2018.$ The number of expected miles over five years is $100,000.$ By what amount would double$-$declining$-$balance depreciation exceed straight$-$line depreciation over the five$-$year life of the truck?

a$.$

The residual value of $$7,000$

b$.$

Cost less total depreciation

c$.$

Cost plus total depreciation

d$.$

Total depreciation expenses under double$-$declining$-$balance and straight$-$line depreciation are equal.