Sabor Inc. is a medical testing laboratory that performs several tests and analyses for hospitals in the area. Four of the tests that they perform require the use of a specialized machine that can supply 14,000 hours per year. Information on the four lab tests follows:

	Test A	Test B	Test C	Test D
Charging rate	$65	$51	$48	$32
Variable cost	$25	$18	$13	$8
Machine hours	3	2	1	0.5

What is the contribution margin per unit of machine time for Test D?

a.$32

b.$20

c.$48

d.$8

e.$24