Costs associated with two alternatives, code-named 9 and 29, being considered by Dodson Corporation are listed below: Alternative 9 Alternative 29 Supplies costs $ 82,000 $ 69,000 Power costs $ 50,000 $ 50,000 Inspection costs $ 30,000 $ 45,500 Assembly costs $ 43,000 $ 32,000 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 of Alternative 9 over Alternative 29? (Negative amount should be indicated by a minus sign. Omit the "$" signs in your response.) Differential cost $