Carlson Inc. uses a standard costing system. The following monthly cost functions apply to its manufacturing overhead items:

Overhead Item	Cost Function
Indirect materials	$2.40 per DLH
Indirect labor	$3.00 per DLH
Utilities	$1.20 per DLH
Insurance	$72,000
Depreciation	$288,000

Information for the month of December is as follows:

Actual overhead costs incurred:
Indirect materials	$187,200
Indirect labor	216,000
Utilities	86,400
Insurance	79,200
Depreciation	288,000
Total	$856,800
Actual direct labor hours worked	72,000
Standard direct labor hours allowed for production achieved	81,000

Carlson uses expected capacity to calculate standard overhead rates. The monthly expected capacity is 75,000 hours. Calculate the variable overhead efficiency variance.

a.$14,400 U

b.$59,400 F

c.28,800 F

d.$45,000 U

e.$7,200 U