3. The service division of Smithberg Industries reported the following results for 2018. Sales Variable Costs Controllable Fixed Costs Average Operating Assets $800,000 $500,000 $125,000 $825,000 Compute the controllable margin and the return on investment for 2018. Management is considering the following independent courses of action in 2019 in order to maximize the return on investment for this division. (Based on original financial information above). Compute the controllable margin and the expected ROI for each proposed alternative. a) Reduce average operating assets by $125,000 with no change in controllable margin. b) Increase sales by $100,000 with no change in the contribution margin percentage (contribution margin ratio)