Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $48,200 Training of machine operators 25,700 Processing returned products 19,700 Scrap processing (disposal) 26,200 Rework 5,100 Preventative maintenance 30,500 Product design 41,600 Warranty work 6,800 Finished goods inspection 22,300 From the provided schedule of activity costs, determine the non-value-added costs. Oa. $51,000 Ob. $226,100 Oc. $114,900 Od. $57,800