According to the PMBOK® Guide, specifically within the section on Interpersonal and Team Skills, Emotional Intelligence (EI) is a critical competency for project managers to lead teams effectively in complex environments.

Definition and Core Pillars: Emotional Intelligence is the ability to identify, assess, and manage the personal emotions of oneself and others. It is often broken down into four key domains: Self-Awareness, Self-Management, Social Awareness, and Relationship Management.

Conflict Resolution and Synergy: In a project environment, different personalities and high-pressure deadlines often lead to friction. A Project Manager with high EI can recognize early signs of " tension " and intervene with empathy and social skills. This prevents minor disagreements from escalating into project-damaging conflicts.

Increasing Cooperation: By building a culture of psychological safety and mutual respect, the PM fosters an environment where team members feel valued. This directly leads to increased cooperation, as team members are more likely to share information, support one another, and align with the project ' s common goals.

Impact on Performance: High EI helps the PM tailor their leadership style to the needs of individual team members, which improves morale and overall project productivity.

Analysis of other options:

Option A: Preparing a project plan is a technical project management skill (Planning). Managing team members is part of " Direct and Manage Project Work, " but EI is the tool used to do it better, not the act of management itself.

Option B: Planning for User Acceptance Testing (UAT) is a quality and scope management activity. It is a technical process and does not directly utilize the core psychological aspects of emotional intelligence.

Option C: Resource allocation is a logistical and analytical task involving the assignment of people or equipment to specific timeframes. It is handled through the " Estimate Activity Resources " and " Develop Schedule " processes.

Per PMI standards, Emotional Intelligence is a " soft skill " that provides the foundation for effective leadership, specifically by helping the project manager reduce tension and build a cooperative team environment.