Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $50,800 Training of machine operators 27,600 Processing returned products 18,700 Scrap processing (disposal) 25,800 Rework 5,400 Preventative maintenance 28,700 Product design 43,400 Warranty work 8,700 Finished goods inspection 23,800 From the above schedule of activity costs, determine the value-added costs. Oa. $174,300 Ob. $232,900 Oc. $150,500 Od. $183,000