Which of the following is a benefit to bringing in a third-party to act as a neutral mediator in a negotiation?

Which of the following is a benefit to bringing in a third-party to act as a neutral mediator in a negotiation?

A mediator rarely has expertise on the issue being negotiated, so they don't infringe on the primary negotiators' roles.

A mediator eliminates any further discussion or disagreement by simply making an arbitrary and final decision in the negotiation.

A mediator can encourage the two parties central to the negotiation to "sit on the same side of the table".

A mediator always eliminates the expression of angry emotions in a negotiation.