1. If variable cost of goods sold totaled $84,800 for the year (16,960 units at $5 each) and the planned variable cost of goods sold totaled $106,800 (13,350 units at $8 each), the effect of the unit cost factor on the change in contribution margin is:

   a.$50,880 decrease

   b.$18,050 decrease

   c.$50,880 increase

   d.$18,050 increase