Connolly Company produces two types of lamps, classic and fancy, with unit contribution margins of $13 and $21, respectively. Each lamp must spend time on a special machine. The firm owns four machines that together provide 18,000 hours of machine time per year. The classic lamp requires 0.2 hours of machine time, the fancy lamp requires 0.50 hours of machine time. How many of each type of lamp must be sold to optimize total contribution margin?

a. 90,000 classic lamps; 0 fancy lamps
b. 0 classic lamps; 9,000 fancy lamps
c. 18,000 classic lamps; 0 fancy lamps
d. 0 classic lamps; 30,000 fancy lamps
e. 10,000 classic lamps; 10,000 fancy lamps