Cournot problem

4 firms (A,B,C,D) globally that make a product with many customers. They set production levels and then let the market determine market clearing price. Firms A,B,C have same cost structure and production process but D has different production process and cost structure. One year ago, firms ABC conspired to exclude D from the market and D lost all customers.

B has total variable costs of $30,000 for producing 15,000 units and $40,000 for producing 20,000 units. Price of product has been constant at $6 per unit in the last year and total industry production is 90,000 units last year. ABC had same market shares as well.

Before D got kicked out of the market, the market shares were 25% each for ABCD.What is the consumer damage from D being kicked out of the market and what is the preliminary damage estimate.