A company's flexible budget for the range of 35,000 units to 45,000 units of production showed variable overhead costs of $2 per unit and fixed overhead costs of $72,000. The company incurred total overhead costs of $148,800 while operating at a volume of 40,000 units. The total controllable cost variance is:

Select one:

a. $6,800 favorable.

b. $6,800 unfavorable.

c. $3,200 favorable.

d. $3,200 unfavorable.

e. $10,000 favorable.