There are three ways a solution will be accepted by the other side. Which of the following constitute the three?

$1$ point

The solution is mutually satisfactory. It is in line with your motivation, but also with theirs.

Identify, on another item of the negotiation, a solution which they want, but which you do not like. Then agree on a trade$-$off.

Use a carrot and stick approach, blended with respect and politeness, to offer solutions and highlight the risks and threats if they do not accept.

Convince the other negotiators by building a demonstration using objective points of reference $($justifications$)$ which are difficult to deny.