JK Builders Co purchases a new excavator costing 40,000. Its expected useful life is 10 years, at which point it is anticipated that the excavator will have a residual value of 6,000.

If the straight-line method of depreciation is used, what is the annual depreciation charge?

(a) 2,800

(b) 3,400

(c) 4,000

(d) 4,600