Managers at Dell Are Deciding Whether to Increase Their Production

Managers at Dell are deciding whether to increase their production of Inspiron laptops by 4,000 per month. With the increased production, the company's revenue will increase by $10 million a month, its cost will increase by $9 million a month, and its total monthly profit will be $30 million. Dell's managers

A) should not approve producing 4,000 more laptops because it will cost the company too much.
B) should approve producing 4,000 more laptops because the marginal benefit of this action exceeds the marginal cost.
C) should approve producing 4,000 more laptops because this will result in a substantial total profit.
D) cannot make a rational decision unless they know what the company's total profit is before the increase in production.