Top Notch Corporation has four operating divisions. The budgeted revenues and expenses for each division for 2020 follows: IIA (Click to view the results of each division.) Closing down any division would result in savings of 70% of the fixed costs of that division. Top management is very concerned about the unprofitable divisions ( A and B ) and is considering closing them for the year. Read the requirements. Requirement 1. Calculate the increase or decrease in operating income if Top Notch closes division A. Begin by calculating Division A's contribution margin. Requirements 1. Calculate the inclease or decrease in operating income if Top Notch closes division A. 2. Calculate the increase or decrease in operating income if Top Notch closes division B. 3. What other factors should the top management of Top Notch consider before making a decision? Data table Further analysis of costs reveals the following percentages of variable costs in each division