Carter Corporation recently announced a bonus plan to be awarded to the manager of the most profitable division. The three division managers are to choose whether ROI or RI will be used to measure profitability. In addition, they must decide whether investment will be measured using gross book value or net book value of assets. Carter defines income as operating income and investment as total assets. The following information is available for the year just ended:

                          

Carter uses a required rate of return of 10% on investment to calculate RI.

Required
Each division manager has selected a method of bonus calculation that ranks his or her division number one. Identify the method for calculating profitability that each manager selected, supporting your answer with appropriate calculations. Comment on the strengths and weaknesses of the methods chosen by each manager.