What procedure is binding and cannot be changed?

Arbitration is the correct answer because it involves a process where disputes are submitted to a neutral third party, known as an arbitrator, who makes a binding decision based on the evidence and arguments presented by both sides. The nature of arbitration is such that once the arbitrator makes a ruling, the parties involved are required to adhere to the decision, and it typically cannot be appealed or changed. This aspect of arbitration distinguishes it from other forms of dispute resolution.

In contrast, mediation is a more flexible process where a mediator helps both parties to communicate and negotiate a resolution, but the outcome is not binding unless both parties reach a mutual agreement. An injunction is a legal order to do or refrain from doing a specific act, and while it is binding, it does not directly pertain to the resolution of disputes between parties in the same way arbitration does. Collective bargaining refers to the process of negotiation between employers and a group of employees (often represented by a union) regarding wages, working conditions, and other employment terms, and while it can lead to binding agreements, the parameters are subject to negotiation and change throughout the process.