Ace Manufacturing produces two products: A and B. Unit contribution margins for A and B are $30 and $60 respectively. Product A uses 2 direct labor hour, and product B uses 4 direct labor hours. Direct labor is Ace's constrained resource. What is the contribution margin per direct labor hour for each product?

a.$30 for Product A and $240 for Product B

b.$15 for Product A and $15 for Product B

c.$240 for Product A and $60 for Product B

d.$240 for Product A and $15 for Product B