Schedule of Activity Costs Quality Control Activities Activity Cost Process audits $48,900 Training of machine operators 25,000 Processing returned products 17,800 Scrap processing (disposal) 24,500 Rework 5,100 Preventative maintenance 31,200 Product design 40,200 Warranty work 9,100 Finished goods inspection 23,200 From the provided schedule of activity costs, determine the internal failure costs. a. $29,600 b. $56,500 c. $96,700 d. $23,680