A Small Nation Has Three Gasoline Suppliers with a Linear

A small nation has three gasoline suppliers with a linear monthly market demand equal to: Q = 500,000 - 5P. Each firm's marginal cost (MC) and average total cost (ATC) curves are horizontal at $10,000 per month.
-Refer to the information above. If the firms' managers form a price- fixing cartel that maximizes the firms' total profit, what is the total economic profit made by all firms?

A) $575,000,000
B) $10,125,000,000
C) 3,375,000,000
D) $54,000,000