问题如下：
Assuming there is no fixed costs, which of the following would most likely leading to higher gross profit margin?
选项：
A.Increasing the number of goods sold.
B.Decreasing the cost of producing each good.
C.Decreasing the costs of administration.
解释：
Decreasing the cost of producing each good would lower the cost of units sold, thus leading to higher pross profit.
Because there is no fixed cost, increasing the number of goods sold will result in no change in gross profit margin.
Gross profit margin contains no administrative expenses.
gross profit margin不是等于EBIT/revenue 吗？
这样的话，不是会包含administrative expenses？
为什么没有固定成本，就没有改变？
麻烦老师详细解释一下
