The root of this conflict is unclear roles and responsibilities. The best action is to eliminate ambiguity by using a Responsibility Assignment Matrix (RAM), such as a RACI chart, to clearly define who is responsible, accountable, consulted, and informed for each task. This reduces confusion and prevents similar conflicts.
Option A resolves the current issue temporarily but doesn't prevent future misalignment.
Option B assumes staffing is the problem, which is unproven.
Option D helps but doesn't formally clarify accountability.
Reference:
PMBOK Guide - Sixth Edition, Section 9.1: Plan Resource Management
PMBOK Guide - Seventh Edition, Team Performance Domain (Roles and Responsibilities)
-