If variable selling and administrative expenses totaled $120,000 for the year (80,000 units at $1.50 each) and the planned variable selling and administrative expenses totaled $136,500 (78,000 units at $1.75 each), the effect of the unit cost factor on the change in contribution margin is: a. $20,000 increase b. $19,500 decrease c. $20,000 decrease d. $19,500 increase

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