Where is the consumer surplus on a monopoly graph?

• A. The space above the total revenue rectangle (triangle)
• B. The area under the demand curve and above price
• C. The rectangle of price times quantity
• D. The triangle below the price line

Answer: (D)

Consumer surplus is the extra value buyers get when they pay a price that's lower than what they’re willing to pay. On a monopoly graph, that surplus shows up as the region between the demand curve and the market price, from zero up to the quantity sold. In other words, it is the area under the demand curve and above the price line (a triangle if the demand is roughly linear). The other descriptions don’t match this idea: the area that equals price times quantity is total revenue, not surplus; a region below the price line would not reflect consumers’ willingness to pay above the actual price; and the “space above the total revenue rectangle” isn’t the standard representation of consumer surplus.