A Single-Price Monopoly Has Marginal Revenue and Marginal Cost Equal

A single-price monopoly has marginal revenue and marginal cost equal to $19 at 15 units of output where the price on the demand curve is $38. At this output, average total cost is $15. What is the total profit earned?

A) $225
B) $285
C) $570
D) $345
E) $19