Edison Company produces two types of piano legs, plain and fancy, which have unit contribution margins of $8 and $12, respectively. Each piano leg must spend time on a special machine. The firm owns four machines that together provide 10,000 hours of machine time per year. The plain leg requires 0.25 hours of machine time, and the fancy leg requires 0.5 hours of machine time. Required: a. What is the contribution margin per hour of machine time for each product? Show and label your work. (3 marks) b. What is the optimal mix of products? Show supporting calculations. (3 marks) c. What is the total contribution margin for the optimal mix? (2 marks) d. List two qualitative factors that Edison Company should consider before making a decision. (2 marks)