Explanation:

- Option 1: Arbitrator

- Correct choice. An arbitrator is a person appointed by two parties to resolve a dispute. They are neutral parties tasked with making a binding decision.

- Option 2: Broker

- Brokers are intermediaries who facilitate agreements or transactions between parties, such as in real estate or finance, but do not resolve disputes.

- Option 3: Valuer

- Valuers assess the worth or value of an asset, like property or art, rather than settle disputes.

- Option 4: Auditor

- Auditors review financial records and practices to ensure accuracy and compliance, not to arbitrate between parties.