On January $1,2012,$ Rabbit Corp. acquired machinery which it depreciated using the straight$-$line method with an estimated useful life of fifteen years and no residual value. On January $1,2017,$ Rabbit estimated that the remaining life of this machinery was six years with no residual value. This change should be accounted for

as a prior period adjustment.

by continuing to depreciate the machinery over the original fifteen year life. $$

as the cumulative effect of a change in accounting principle in $2017.$

by setting future annual depreciation equal to one$-$sixth of the book value on January $1,2017.$