Final answer:
In third-party negotiations, a conciliator provides an informal link between the negotiator and the opponent, facilitating dialogue without making any decisions.
Step-by-step explanation:
In third-party negotiations, when an informal approach has not worked and there is a need to bring a neutral third party to provide an informal communication link between the negotiator and the opponent, the role is often filled by a conciliator. This individual does not make any decisions but assists the parties in resolving by improving communication, offering suggestions, and providing a channel for the exchange of information. Unlike a mediator who actively helps the parties find a resolution or an arbitrator who makes a binding decision, the conciliator acts more as a facilitator of dialogue. Therefore, the correct answer to the student's question is d. conciliator.