According to the PMBOK® Guide (Project Management Body of Knowledge), specifically within the Project Schedule Management knowledge area and the Define Activities process:

Decomposition (Option A): This is the primary tool and technique used for dividing and subdividing the project scope and project deliverables into smaller, more manageable parts. While decomposition is also used in the Create WBS process to create work packages, in the Define Activities process, it is used to further break down those work packages into specific activities, which represent the actual effort required to complete the work.

Inspection (Option B): This is a tool used in Control Quality and Validate Scope. It involves examining work products to determine if they conform to standards and requirements. It is not used for planning or breaking down work.

Project Analysis (Option C): This is a general term and not a specific PMBOK tool or technique for this process. Related terms like " Product Analysis " are used in Define Scope to translate high-level descriptions into tangible deliverables.

Document Analysis (Option D): This is a data gathering technique used in the Collect Requirements and Identify Stakeholders processes. It involves eliciting requirements by analyzing existing documentation and identifying information relevant to the requirements.

In the PMI framework, Decomposition ensures that the project team has a clear understanding of the work that needs to be performed. By breaking work packages down into activities, the Project Manager can more accurately provide estimates for schedule and cost, which are then used to develop the Schedule Baseline.