Monroe Manufacturing produces and sells a product with a price of $100/unit. The following data has been prepared for its estimated upper and lower levels of activity.

Production Category	Lower Limit	Upper Limit
Units of Production	4,000 units	6,000 units
Direct Materials	$60,000	$90,000
Direct labour	$80,000	$120,000
Manufacturing Overhead:
Indirect materials	$25,000	$37,500
Indirect labour	$40,000	$50,000
Depreciation	$20,000	$20,000
Selling and Admin. Expenses:
Sales salaries	$50,000	$65,000
Office salaries	$30,000	$30,000
Advertising	$45,000	$45,000
Other	$15,000	$20,000
Totals	$365,000	$477,500

The variable expenses for Monroe Manufacturing are

		all categories of selling and administrative expenses.
		direct materials, direct labour, sales salaries.
		indirect materials, indirect labour, direct materials, and direct labour
		indirect materials, direct materials, and direct labou