A change from the straight$-$line method to the sum$-$of$-$years'$-$digits method of depreciation is handled as:

A$.$ A retrospective change back to the date of acquisition as though the current estimated life had been use

B$.$ A cumulative adjustment to income in the current year for the difference in depreciation under the new

C$.$ A prospective change from the current year through the remainder of its useful life

D$.$ None of the above is correct