Detailed Answer
Answer (C) is correct. Residual income is the excess of the amount of the ROI over a targeted amount equal to an imputed interest charge on invested capital. If a manager has $19,000,000 of invested capital ($17,200,000 of plant and equipment + $1,800,000 of working capital), a 15% imputed interest charge equals $2,850,000. Adding $2,000,000 of residual income to the imputed interest results in a target profit of $4,850,000. This profit can be achieved if costs are $25,150,000 ($30,000,000 revenue – $4,850,000 profit).