Cubic Inc. acquired some manufacturing equipment in January $2015$ for $$400,000$ and depreciated it $$40,000$ each year for three years on a straight$-$line basis. During $2018,$ the manufacturer announced a new technology for this type of equipment that will make the old models obsolete by the end of $2021.$ As a result, Cubic will plan to replace the equipment at that time, effectively reducing the asset's life from ten to seven years. In its financial statements for $2018,$ Cubic should: A$.$ Charge $$280,000$ in depreciation expense, B$.$ none of these answer choices are correct, C$.$ make an adjustment to retained earnings for the error in measuring depreciation during $2015-2017,$ or D$.$ report the book value of the requipment in its December $31,2018$ balance sheet at $$210,000.$