The project manager should have established ground rules for the team at the beginning of the project, which would include guidelines for communication, decision making, conflict resolution, and stakeholder engagement. Ground rules help the team to work effectively and collaboratively, and to avoid misunderstandings and disagreements. Providing copies of the stakeholder engagement plan (A) is not enough, as it does not specify how the team should interact with the stakeholders. Defining the roles and responsibilities of the team members (B) is also important, but it does not address the issue of who should attend the meeting with the local council authority. Updating the communications management plan is not relevant, as it does not prevent the conflict from occurring in the first place. References: PMBOK Guide, 7th edition, page 91; Agile Practice Guide, page 14.