According to the PMBOK® Guide and the Standard for Project Management, specifically within the Project Integration Management Knowledge Area, Expert Judgment is a primary tool and technique used in the Develop Project Management Plan process.

As per PMI standards, Develop Project Management Plan is the process of defining, preparing, and coordinating all plan components and consolidating them into an integrated project management plan. Expert Judgment is defined as judgment provided based upon expertise in an application area, Knowledge Area, discipline, industry, etc., as appropriate for the activity being performed. In this specific process, expert judgment is used to:

Tailor the Process: Determine which processes from the PMBOK® Guide are appropriate for the specific project.

Develop Technical Details: Provide expertise on the technical and management details to be included in the plan.

Determine Resources: Assist in determining the resources and skill levels needed to perform project work.

Define Management Levels: Establish the level of configuration management and change control to be applied to the project.

The other options are incorrect based on their specific placement within the PMI framework:

Pareto diagram: This is a Quality Management tool (a vertical bar chart) used in the Manage Quality and Control Quality processes to identify the vital few sources that are responsible for causing the most causes of effects.

Performance reporting: This is part of the Monitor and Control Project Work and Manage Communications processes. It involves collecting and distributing performance information, including status reports and progress measurements, rather than planning how the project will be managed.

SWOT analysis: As seen in previous questions, this is a tool used in the Identify Risks process to identify strengths, weaknesses, opportunities, and threats.

Expert Judgment is also used in many other processes (like Develop Project Charter or Define Scope), but among the choices provided, it is the only one listed as an official tool/technique for the Develop Project Management Plan process.

As per the PMI Lexicon of Project Management Terms, Expert Judgment ensures that the Project Management Plan is realistic, comprehensive, and based on proven organizational or industry practices.