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 Supervising other $ 3,800 $ 23,800 $ 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: Batches (Supervising) 500 500 MHS (Processing) 9,700 300 Product MO Product M5 Total 10,000 1,000 Finally, sales and direct cost data are combined with Processing and Supervising costs to determine product margins. Product MO $ 74,100 Product M5 $ 89,900 Sales (total) Direct materials (total) Direct labor (total) $ 28,500 $ 27,800 $ 31,400 $ 41,700 The activity rate for the Supervising activity cost pool under activity-based costing is closest to