A Small Coffee Company Roasts Coffee Beans in Its Shop

A small coffee company roasts coffee beans in its shop. The unroasted beans cost the company $2 per pound. The marginal cost of roasting coffee beans is $ per pound when q pounds are roasted. The smell of roasting beans imposes costs on the company's neighbors. The total amount that neighbors would be willing to pay to have the shop stop roasting altogether is 5q², where q is the number of pounds being roasted. The company sells its output in a competitive market at $4.50 per pound. What is the socially efficient amount of coffee for the company to roast?

A) 10 pounds.
B) 15 pounds.
C) the square root of 10 pounds.
D) 45 pounds.
E) None of the above.