The following data are from the accounting records of Niles Castings for year 2. Units produced and sold Total revenues and costs Sales revenue Direct materials costs Direct labor costs Variable manufacturing overhead Fixed manufacturing overhead Variable marketing and administrative costs Fixed marketing and administrative costs Required: a. Prepare a gross margin income statement. b. Prepare a contribution margin income statement. 80,000 $320,000 67,000 37,000 18,000 49,000 12,500 34,000