Korsak Corporation is a service company that measures its output by the number of customers served. The company has provided the following fixed and variable cost estimates that it uses for budgeting purposes.

	Fixed Element per Month			Variable Element per Customer Served
Revenue				$	5,500
Employee salaries and wages	$	43,700		$	1,100
Travel expenses				$	500
Other expenses	$	43,200

The planning budget for October was based on serving 23 customers, but a total of 19 customers were actually served during October.

The activity variance for net operating income for October would have been closest to: