Rainy Corporation reported the following results for December: Description Amount Number of units sold 700 units Selling price per unit $400 per unit Cost of goods sold per unit (all variable) $150 per unit Variable selling expense per unit $25 per unit Fixed selling expense $12,000 Variable administrative expense per unit $22 per unit Fixed administrative expense $14,300 The gross margin for December is: O A $142,100 B. $175,000 c. $247.100 OD. $148,700