可以解释一下这个题的考点吗

问题如下：

Which of the following best describes the underlying rationale for a written investment policy statement (IPS)?

选项：

A.

A written IPS communicates a plan for trying to achieve investment success.

B.

A written IPS provides investment managers with a ready defense against client lawsuits.

C.

A written IPS allows investment managers to instruct clients about the proper use and purpose of investments.

解释：

A  is correct.

A written IPS is best seen as a communication instrument allowing clients and portfolio managers to mutually establish investment objectives and constraints.