According to the PMBOK® Guide, the Plan Scope Management process is the process of creating a scope management plan that documents how the project scope will be defined, validated, and controlled.

Expert Judgment: This is a primary tool and technique used in the initial development of the Project Scope 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.

Application in Scope Planning: For this specific process, expertise should be sought from individuals or groups with specialized knowledge or training in:

Previous similar projects.

Information in the industry, discipline, and application area.

Developing scope management plans and requirements management plans.

Other Tools in Plan Scope Management: In addition to expert judgment, Data Analysis (specifically alternatives analysis) is used to evaluate different ways of creating the scope management plan and managing the scope.

Analysis of Other Options:

A. Alternatives identification: This is a technique used during the Define Scope process to generate different approaches to execute and perform the work of the project.

B. Scope decomposition: This is the primary technique for the Create WBS process, where the project scope and project work are subdivided into smaller, more manageable components.

D. Product analysis: This is a technique used in the Define Scope process for projects that have a product as a deliverable (as opposed to a service or result). It involves asking questions about a product and forming answers to describe the use, characteristics, and other relevant aspects of the product.