Glassing Clinic uses client-visits as its measure of activity. During September, the clinic budgeted for 3,820 client-visits, but its actual level of activity was 3,780 client-visits. The clinic has provided the following data concerning the formulas to be used in its budgeting: Varlable Fixed element per element per month client-visit $22.60 Revenue $ 5.80 Personnel expenses $22,050 Medical supplies 865 4.70 Occupancy expenses 4,360 2.30 Administrative expenses 3,265 1.20 $30,540 14.00 Total expenses The activity variance for net operating income in September would be closest to: O $344 U O $3,504 U $3,504 F O $344 F