Presented below is sected information for three regional divisions of Medina Company. Contribution margin Controllable margin Average operating assets Minimum rate of return North $300,900 $139,500 $930,000 13 % Divisions West $500,300 $360,000 $2,000,000 14 % South $400,800 $211,500 $1,410,000 10 % (a) Compute the return on investment for each division North Division % West Division %6 South Division %