Rhed kennel uses tenant-days as its measure of activity; an animal housed in the kennel for one day is counted as one tenant-day. during december, the kennel budgeted for 4,200 tenant-days, but its actual level of activity was 4,150 tenant-days. the kennel 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 tenant-day revenue - $ 34.90 wages and salaries $ 3,200 $ 8.70 food and supplies 1,900 13.90 facility expenses 9,200 5.40 administrative expenses 7,200 0.60 total expenses $ 21,500 $ 28.60 actual results for december: revenue $ 144,135 wages and salaries $ 39,590 food and supplies $ 58,505 facility expenses $ 31,760 administrative expenses $ 7,780 the activity variance for administrative expenses in december would be closest to: