Nicklin Corporation is considering two alternatives, code-named M and N. Costs associated with the alternatives are listed below: Supplies costs Power costs Inspection costs Assembly costs Alternative M $ 69,000 $ 42,000 $22,000 35,000 Alternative N 61,000 $ 42,000 $ 33,500 $ 24,000 Required a. Which costs are relevant and which are not relevant in the choice between these two alternatives? Supplies costs Power costs Inspection costs Assembly costs elevant ot relevant Relevant elevant b. What is the differential cost between Alternative M and Alternative N? (Negative amount should be indicated by a minus sign.) Differential cost$ 7,500