问题如下：
Which of the following descriptions about normal profit is incorrect?
选项：
A.It is the difference between total revenue and total explicit cost.
B.It is minimum requirement for a firm to continue operating in the long run.
C.It is the accounting profit that makes economic profit zero.
解释：
A is correct.
Accounting profit rather than normal profit is the difference between total revenue and total explicit cost.
考点：Normal profit
解析：
正常利润应该等于收入减去显性成本的同时还要减去隐性成本。A选项入选
正常利润就是经济利润为0时候的利润，如果企业想要在长期维持生存就必须获取正常利润，所以B，C选项不入选。
所以difference between total revenue and explicit cost = AP 不是 NP对吗？
