Before responding to the concern, the project manager should review the stakeholder engagement plan to confirm whether this key stakeholder was properly consulted and involved. This step ensures that engagement strategies are aligned with project objectives and that no stakeholder was missed in the planning phase. The PMBOK Guide - Seventh Edition emphasizes the importance of identifying, analyzing, and engaging all stakeholders appropriately, especially in sensitive public sector projects. Option B is dismissive and can escalate conflict. Option C assumes prior engagement without confirmation. Option D is premature without validating the engagement process. References: PMBOK Guide - Seventh Edition, Stakeholder Performance Domain PMI Stakeholder Engagement Practice Guide ##############################################