Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $48,300 Training of machine operators 25,800 Processing returned products 17,300 Scrap processing (disposal) 26,200 Rework 8,600 Preventative maintenance 28,200 Product design 44,500 Warranty work 8,700 Finished goods inspection 22,500 From the provided schedule of activity costs, determine the value-added costs. Oa. $230,100 Ob. $178,000 Oc. $169,300 Od. $146,800