Which of the following statements about total profit, marginal profit or average profit curve is correct ( ).
选项：

A:The total profit is maximum when the marginal profit is zero
B:Total profit reaches its maximum when average profit and marginal profit curves intersect
C:As average profits rise, marginal profits increase
D:Average profit reaches maximum when marginal profit and average profit curve intersect
E:The marginal profit curve increases and then decreases until it becomes negative