Mirabile 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 $ 4,500 Supervising $ 26,640 Other $11.700 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: Machine-hours (Processing) Batches (Supervising) Product MO 9,500 600 Product M5 500 600 Total 10,000 1,200 Finally, sales and direct cost data are combined with Processing and Supervising costs to determine product margins. Product MO Product M5 Sales (total) $ 83,100 $ 96,400 Direct materials (total) $ 29,800 $ 32,700 Direct labor (total) $29,100 $ 43,000 The activity rate for the Supervising activity cost pool under activity-based costing is closest to