S'Round Sound, Inc. reported the following results from the sale of 30,000 units of IT-54:

Sales	$543,000
Variable manufacturing costs	300,000
Fixed manufacturing costs	180,000
Variable selling costs	54,600
Fixed administrative costs	36,900

Rhythm Company has offered to purchase 3,900 IT-54s at $15 each.

Sound has available capacity, and the president is in favor of accepting the order. She feels it would be profitable because no variable selling costs will be incurred.

The plant manager is opposed because the "full cost" of production is $16.

Which of the following correctly notes the change in income if the special order is accepted?

Group of answer choices

$19,500 increase.

$3,900 decrease.

$3,900 increase.

$19,500 decrease.

None of these.