Lizana Clinic uses client-visits as its measure of activity. During December, the clinic budgeted for 4,700 client-visits, but its actual level of activity was 4,680 client-visits. The clinic has provided the following data concerning the formulas used in its budgeting and its actual results for December Data used in budgeting: Fixed element per month Variable element per client visit Revenue $36.70 Personnel expenses $28,700 $12.70 Medical supplies 1,600 6.70 Occupancy expenses 10,600 1.00 Administrative expenses 7,700 0.30 Total expenses $48,600 $20.70 Actual results for December: Revenue $131,000 Personnel expenses $70,030 Medical supplies $21,014 Occupancy expenses $13,200 Administrative expenses $7,450 The activity variance for net operating income in December would be closest to: