Costs associated with two alternatives, code-named Q and R, being considered by Lang Corporation are listed below: Alternative Q Alternative R Supplies costs $ 63,100 $ 63,100 Power costs $ 36,400 $ 20,400 Inspection costs $ 11,500 $ 27,900 Assembly costs $ 37,900 $ 29,000 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 b. What is the differential cost between the two alternatives