What Happens at the Third Level of the Pyramid Model

What happens at the third level of the pyramid model of integrative agreements?

A) Negotiators reach an agreement below both parties' reservation points.
B) Both parties' reservation points are too high to reach an agreement.
C) Negotiators fail to reach an agreement when the bargaining zone is positive.
D) Both parties achieve an agreement that cannot be improved for one party without harming the other party.