Khanam Corporation, which has only one product, has provided the following data concerning its most recent month of operations:

Selling price	$133
Units in beginning inventory	950
Units produced	8,850
Units sold	8,950
Units in ending inventory	850
Variable costs per unit:
Direct materials	$29
Direct labor	$46
Variable manufacturing overhead	$10
Variable selling and administrative	$20
Fixed costs:
Fixed manufacturing overhead	$70,800
Fixed selling and administrative	$164,200

The company produces the same number of units every month, although the sales in units vary from month to month. The company's variable costs per unit and total fixed costs have been constant from month to month.

What is the net operating income for the month under variable costing?

$14,800

$15,600

$4,100

$24,100

Please Explain