Leist Clinic uses client-visits as its measure of activity. During September, the clinic budgeted for 2,200 client-visits, but its actual level of activity was 2,170 client-visits. The clinic has provided the following data concerning the formulas to be used in its budgeting: The medical supplies in the flexible budget for September would be closest to:

A) $22,080
B) $21,798
C) $21,907
D) $21,313

Medical supplies are a variable cost, so we need to use the formula for variable costs in the flexible budget:

Flexible budget for variable costs = Actual level of activity x Variable cost per unit

From the data given in the question:

- Actual level of activity = 2,170 client-visits
- Variable cost per unit of medical supplies = $10.05

Plugging these values into the formula above:

Flexible budget for variable costs = 2,170 x $10.05 = $21,798

Therefore, the closest option is B) $21,798.