A Good Marketing Manager for a Producer Knows That the Most

A good marketing manager for a producer knows that the most profitable price and level of output:

A) is where the positive difference between the total revenue and total cost curves is the greatest.
B) is where the difference between marginal revenue and marginal cost is the greatest.
C) is where total revenue equals total cost.
D) is where marginal revenue is maximized.
E) Both A and C are true.