What is Activity rate in this question

Sky Castle Corporation has provided the following data from its activity-based costing system: Activity Cost Pool Total Cost Total Activity. Assembly $443,100 35,000 machine- hours Order processing $32,930 1,000 orders Scheduling $106,596 1,410 schedules Data concerning one of the company's products, Laputa, appear below: Selling price per unit $88.20 Direct material cost per unit $15.62 Direct labour cost per unit $12.80 Annual production and sales 300 unit Annual machine-hours 870 Annual orders 90 Annual number of schedules 30 The activity rate for the Order Processing activity cost pool is closest to