Calculator Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $51,100 Training of machine operators 28,800 Processing returned products 18,100 Scrap processing (disposal) 26,900 Rework 5,500 Preventative maintenance 27,300 Product design 45,300 Warranty work 8,600 Finished goods inspection 23,000 From the above schedule of activity costs, determine the external failure costs. Ca. $59,100 b. $26,700 c. $21,360 d. $87,900