Explanation
The project manager should foster knowledge sharing and coaching among team members to address the slack in productivity caused by the lack of knowledge in one of the frameworks used for modeling. This way, the project manager can leverage the existing skills and expertise of the team members who are familiar with the framework, and help the others to learn and improve their performance. The project manager can also use various agile techniques, such as pair programming, peer reviews, retrospectives, and feedback loops, to facilitate knowledge sharing and coaching. The project manager should not seek an external expert, arrange for external training, or add new members, as these options may be costly, time-consuming, or disruptive to the team dynamics and collaboration. References: PMBOK Guide, 6th edition, page 349, Top 60+ PMP Exam Questions and Answers for 2023 - KnowledgeHut