Smith Company owns 3 machines that provide 12,900 machine hours per year. Part X requires 1.5 hours, and Part Y requires 0.5 hour. The respective unit contribution margins for Part X and Y are $48 and $27. If a maximum of 15,600 units of each part can be sold, what is the. maximum contribution margin? a. $584,400 b. $568,800 c. $612,900 d. $876,900