Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $48,200 Training of machine operators 29,800 Processing returned products 17,600 Scrap processing (disposal) 25,400 Rework 8,700 Preventative maintenance 31,000 Product design 42,400 Warranty work 8,600 Finished goods inspection 22,700 From the provided schedule of activity costs, determine the prevention costs. Oa. $60,800 Ob. $103,200 Oc. $111,900 Od. $120,800