Conflict resolution starts with understanding the root cause of the issue. Before taking corrective or disciplinary action, the project manager should investigate both sides to identify what is causing the tension. This is essential for resolving the issue constructively and preventing recurrence. This approach aligns with the PMBOK Guide - Seventh Edition guidance on conflict management: listen first, then act. Option A presumes the team member is at fault. Option B may not be suitable without understanding this context. Option D is helpful later, not as the first step. References: PMBOK Guide - Seventh Edition, Team Performance Domain PMI Conflict Management and Leadership Guidelines ##############################################