Which of the following roles represents the interests of one party in a negotiation?

The role that represents the interests of one party in a negotiation is a negotiator. A negotiator actively engages in discussions and bargaining on behalf of a specific party, aiming to achieve favorable terms and outcomes that align with that party's goals and objectives. This role is focused on advocacy and representation, ensuring that the needs and interests of the party they represent are articulated and pursued during the negotiation process.

In contrast, a mediator does not represent either party but instead facilitates discussion between them to help reach a mutual agreement. An arbitrator also does not advocate for one side; instead, they listen to both parties and make a binding decision based on the merits of the case presented. Likewise, a facilitator helps guide the negotiation process and makes it smoother, often without taking sides or representing any individual interests. Each of these roles serves different functions within the negotiation spectrum, but the negotiator specifically embodies the interests of their designated party.