The figure provided represents the domestic market for cars. A graph plots domestic supply curve and domestic demand curve with Quantity of cars along the horizontal axis and Price of cars along the vertical axis. The Domestic supply curve has a positive slope, and the Domestic demand curve has a negative slope. The curves intersect at QA in quantity of cars, PA on price of cars. A horizontal line starts from PW on price of cars and intersects the domestic supply curve at quantity B and the domestic demand curve at quantity C. The line is labeled PW. The area below the domestic demand curve bounded by PA on Price of cars is labeled as A. The area between PA and PW on price of cars bounded by the domestic supply curve is labeled as B. The area below PW on the price of cars bounded by the domestic supply curve is labeled as C. The area below the domestic demand and supply curves bounded by PW line is labeled as D. The gain in total surplus after trade is the area _____. D B A + B A + C