B Company Switched from the Sum-Of-The-Years-Digits Depreciation Method to Straight-Line

B Company switched from the sum-of-the-years-digits depreciation method to straight-line depreciation in 2009. The change affects machinery purchased at the beginning of 2007 at a cost of $72,000. The machinery has an estimated life of five years and an estimated residual value of $3,600. What is B's 2009 depreciation expense?

A) $ 8,400
B) $13,680
C) $15,840
D) $19,200 The depreciation prior to the change is as follows:
Since a change in depreciation method is considered a change in accounting estimate resulting from a change in accounting principle, B reports the change prospectively, just like a change in estimate.B depreciates the remaining undepreciated cost on a S-L basis over the remaining useful life: