Upsilon Inc. is a chemical testing laboratory that performs several tests and analyses for manufacturers 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 $65 $51 $48 $32 Charging rate Variable cost Machine hours $25 $27 $13 $8 3 2 1 0.5 What is the contribution margin per unit of machine time for Test B? $20 $12 $24 $48