The project manager should first try to address the issue of team members not following the ground rules by scheduling a meeting with the project team to reinforce the ground rules. This is the most proactive and collaborative approach to resolve the problem and ensure team adherence to the ground rules. The project manager should also use this opportunity to listen to the team members' feedback and concerns, and make any necessary adjustments to the ground rules to suit the project context and team dynamics. This is consistent with the agile principles of self-organizing teams, frequent communication, and continuous improvement. The other options are not the best choices, as they involve escalating the issue to external parties, such as the project sponsor, human resources, or the functional manager, without first trying to resolve it within the team.
These options may also create a negative impact on the team morale, trust, and performance, and undermine the project manager's leadership and authority. References: (Professional in Business Analysis Reference Materials source and documents) A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition, Chapter 9:
Project Team Management, Section 9.2.2: Team Charter
Business Analysis for Practitioners: A Practice Guide, Chapter 5: Elicitation and Collaboration, Section 5.3.1:
Ground Rules
Agile Practice Guide, Chapter 2: An Introduction to Agile, Section 2.3: Agile Teams