问题如下：
Which of the following will make economic profits be 0?
选项：
A.When explicit costs and implicit costs is the same amount.
B.When the total revenue is equal to explicit costs.
C.When the sum of explicit costs and implicit costs is equal to total revenue.
解释：
C is correct.
Economic profit = total revenue – explicit cost - implicit cost.
Therefore, when total revenue is equal to the sum of explicit and implicit opportunity costs, economic profit is zero.
考点：经济利润
解析：因为经济利润=总收入-显性成本-隐形成本。
因此，当总收入等于显性和隐性机会成本之和时，经济利润为零。
老师，把B改为，When the total revenue is equal to explicit costs and implicit cost is 0, 是不是就正确了？
