Walsh Corporation uses activity-based costing to compute product margins. Overhead costs have already been allocated to the company's three activity cost pools --Processing, Supervising, and Other. The costs in those activity cost pools appear below: Processing $ 3,800 Supervising $ 23,800 Other $ 10,400 Processing costs are assigned to products using machine-hours (MHs) and Supervising costs are assigned to products using the number of batches. The costs in the other activity cost pool are not assigned to products. Activity data appear below: 300 MHs (Processing) Batches (Supervising) Product MO 9,700 500 Product M5 500 Total 10,000 1,000 Finally, sales and direct cost data are combined with Processing and Supervising costs to determine product margins. Product MO Product M5 Sales (total) $74,100 $89,900 Direct materials (total) $28,500 $31,400 Direct labor (total) $27,800 $41,700 What is the product margin for Product M5 under activity-based costing? Select one: a. $2,686 b. $4,786 c. $18,000 d. $16,800