Answer:
The Answer is C.
Explanation:
Why did I choose C? Let's break it down.
1st of all, your aim is to promote a "greater sense of fairness among your employee".
This puts option A out of the box. If the employees are doing good and you try to find support for giving lower evaluations, certainly it will not work and employees will resist this, leading to unnecessary conflicts.
Option B is from my point of view, Silly! You tell them that the company can't pay enough and ask employees to file grievances? Like when did that work out? If this to work, when you file for grievances, the company should magically get cash and able to pay you!
You can go for the Option D and stay away from the whole scenario, yet this is not a solution at all. Isn't it? So we can throw it out of the window too.
Option C is the most logical one, since you carry out the evaluation sincerely and then give your employees a true explanation.