Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $50,000 Training of machine operators 25,900 Processing returned products 15,100 Scrap processing (disposal) 25,300 Rework 7,000 Preventative maintenance 27,000 Product design 41,400 Warranty work 10,000 Finished goods inspection 22,000 From the above schedule of activity costs, determine the value-added costs. Oa. $223,700 Ob. $144,300 Oc. $166,300 Od. $176,300