If variable cost of goods sold totaled $82,985 for the year (16,597 units at $5 each) and the planned variable cost of goods sold totaled $101,297 (14,471 units at $7 each), the effect of the quantity factor on the change in contribution margin is: Oa. $14,882 increase Ob. 510,630 increase Oc 510,630 decrease Od. $14,882 decrease