Please help me complete this, I have been struggling for a while and mainly I need the answer. Give Kudos!

All other things equal, which of the following would increase a division's residual income? A) Increase in expenses. B) Decrease in average operating assets. C) Increase in minimum required return. D) Decrease in net operating income. At the beginning of this year, the company has a $1,100,000 investment opportunity with the following characteristics: Sales $ 1,980,000 Contribution margin ratio 40% of sales Fixed expenses $ 653,400 Last year's return on investment (ROI) was closest to: A. 10% B.5% C.50% 0.64.3%