Zacher Corporation makes a product with the following standards for direct labor and variable overhead:

	Standard Quantity or Hours	Standard Price or Rate		Standard Cost Per Unit
Direct labor	0.3 hours	$24.00	per hour	$7.20
Variable overhead	0.3 hours	$10.00	per hour	$3.00

In February, the company's budgeted production was 4,400 units, but the actual production was 4,650 units. The company used 1,230 direct labor-hours to produce this output. The actual variable overhead cost was $13,131. The company applies variable overhead on the basis of direct labor-hours. The variable overhead efficiency variance for February is:

$1,690 F

$1,650 F

$1,690 U

$1,650 U