A和B是那个知识点，分别什么意思啊？

问题如下：

Which of the following statements concerning board policies and practices is least likely correct?

选项：

A.

A one-tier board structure is the most common board structure.

B.

A two-tier board structure consists of a supervisory board that oversees a management board

C.

Many OECD countries introduce a recommendation for the minimum ratio of independent directors serving on the board: range of 10%–20% or greater

解释：

C is correct.

The absence or presence of a minority of independent directors is a negative aspect of corporate governance.

Many OECD countries introduce a recommendation for the minimum ratio of independent directors serving on the board: range of 20%–50% or greater.