On January $1,2013,$ Zane Manufacturing Company purchased a machine for $$40,000.$ The company expects to use the machine a total of $24,000$ hours over the next $6$ years. The estimated sales price of the machine at the end of $6$ years is $$4,000.$ The company used the machine $8,000$ hours in $2013$ and $12,000$ in $2014.$

What is depreciation expense for $2013$ if the company uses straight$-$line depreciation?

a$.$ $$12,000$

b$.$ $$6,667$

c$.$ $$6,000$

d$.$ $$13,333$