A monopolist's profit-maximizing quantity of its product is 10 units. The economically efficient quantity supplied of the product is 14 units. Consumers' valuations of the 11th, 12th, 13th and 14th units of the product are. respectively, $20, $17, $14 and $11. The monopolist's marginal cost of production is constant at $11 per product unit. What is the size of the deadweight loss caused by the monopolist choosing to supply 10 units of its product?