Comprehensive and Detailed Explanation: When a critical project is delayed, especially one impacting multiple stakeholders (e.g., branch offices), a proactive and direct communication method is best. A video conference enables two-way communication, clarity, and immediate response to concerns. This supports stakeholder engagement, transparency, and relationship-building. Option A (group chat) is too informal and may cause misunderstandings. Option C (memo) is one-way communication and may lack context. Option D (monthly report) delays the message unnecessarily. References: PMBOK Guide - Seventh Edition, Stakeholder and Communication Performance Domains PMI Stakeholder Engagement Planning Guidance ##############################################