Answer: c. $18,000 increase
Step-by-step explanation:
Department margin was $100,000 in September.
October Margin = Sales - Variable Costs - Traceable Fixed Costs
= (2,000 *( 210 - 25 - 80 - 15) ) - 62,000
= (2,000 * 90) - 62,000
= $118,000
= October Margin - September Margin
= 118,000 - 100,000
= $18,000 increase