The company Digitale manufactures 2 models - Super and Ultra - of commercial "digital reproduction equipment". Super sells for $ 4,800. Ultra sells for $7,500. The relevant variable costs are $ 2,400 for the Super model and $ 4,500 for the Ultra model. Type recognize machine hours as a restriction factor. 4 machine hours are required to finish a Super unit. 10 machine hours are required to finish an Ultra unit. Digitales management determines which of the two equipment models is the most profitable (profitable) recognizing that there is a machine hours restriction factor. What should be the basis for making the decision to make one or the other model? Select one: A. Which model contributes a higher marginal contribution per unit. b. Which model contributes a higher marginal Contribution calculated on the basis of machine hours. c. The production of the Superior model or Ultra model is indifferent since both models have the same marginal contribution and therefore are equally profitable. d. Which model contributes a higher operating income