5 Calculator Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $51,800 Training of machine operators 28,900 Processing returned products 18,000 Scrap processing (disposal) 27,000 Rework 7,900 Preventative maintenance 27,300 Product design 40,100 Warranty work 9,600 Finished goods inspection 23,400 From the above schedule of activity costs, determine the external failure costs. a. $62.500 b. $27,600 c. $91.400 d. $22.080