The correct answer is:

Its irrelevance to business objectives

and

Its effect on team motivation

Rationale: Team members may work for individual rewards, rather than contributing to the group, especially since there is a problem offering rewards for less measurable criteria such as team-work.

Its irrelevance to business objectives is incorrect as PRP relates rewards directly to business objectives.

Its effect on organisational communication is clearly a benefit.

You may have hesitated over the fact that it does not relate to individuals' wage or salary grades but this is a benefit because PRP is a way of rewarding employees when there is no other way to do so (eg because they have reached the top of the salary/wage range their position is eligible for).