A price-making business must follow the one-price rule and faces the following demand schedule: at prices of $7, $6, $5, $4, and $3, quantity demanded is 300, 400, 500, 600, and 700 units respectively. If the business's marginal cost is constant at $150, it maximizes profits by producing

Select one:

A.

400 units and charging a price of $6.

B.

600 units and charging a price of $4.

C.

300 units and charging a price of $7.

D.

700 units and charging a price of $3.

E.

500 units and charging a price of $5.

what is the answer and why?