operating margin 怎么算的

问题如下：

The following data is available on two companies that operate in the same industry:

Which of the following statements is most appropriate? Better margin performance will be reported by:

选项：

A.X at the gross margin level and Y at the operating margin level. B.Y at the gross margin level and X at the operating margin level. C.Y at both the gross margin and operating margin levels.

解释：

Common size statements offer a convenient way to compare companies of different magnitudes. Company X reports better (higher) gross margin performance. Company Y reports better (higher) operating margin performance.