The unit product cost of part A is computed as follows: Direct materials 17.80 W Direct labour 19.00 Variable manufacturing 1.00 overhead Fixed manufacturing overhead 17.10 Unit product cost 54.90 An outside supplier has offered to sell the company all of these parts it needs for 48.50 a unit. If the company accepts this offer, the facilities now being used to make the part could be used to make more units of a product that is in high demand. The additional contribution margin on this other product would be 273,000 per year. If the part were purchased from the outside supplier there would be an unavoidable fixed overhead cost of 8.20 being applied to the part, it would continue even if the part were purchased from the outside supplier. How much of the unit product cost of 54.90 is relevant in the decision of whether to make or buy the part? O a 37.80 Ob 19.00 O c. 54.90 O d. 46.70