The pre-built Workforce module in Oracle EPM Planning is designed with a specific, fixed dimensionality, which includes a limited number of custom dimensions (typically two). A primary driver for creating a custom BSO (Block Storage Option) plan type is when a client's business requirements for workforce planning exceed these structural limitations. If a client needs to plan and analyze workforce data by more than the available custom dimensions (for example, by Project, Skill Set, and a custom Geography dimension), the standard Workforce module cannot be configured to accommodate this. A custom BSO plan type provides the necessary flexibility to design a cube with any number of required dimensions.

A. Planning salary by Position is a standard capability of the pre-built Workforce module and does not require a custom solution. C. Different levels of granularity within a shared dimension like Entity are managed through hierarchy design and security, not by creating a new plan type. D. The total number of dimensions in the application is not the direct driver; the specific dimensional requirements for the workforce planning process itself are what matter. E. A custom BSO cube would likely suffer from the same slow aggregation performance if it has similar size and sparse dimensionality. The standard architectural solution for slow BSO aggregation is typically an ASO (Aggregate Storage Option) reporting cube, not another BSO cube.

1. Oracle EPM Cloud, Administering Planning, Chapter 8: About Workforce: The documentation outlines the structure of the pre-built Workforce business process. It states, "Workforce provides two custom dimensions that you can enable and define to analyze expenses by dimensions that are not part of the predefined dimensions..." This confirms the limitation on the number of custom dimensions, directly supporting why option B is a valid reason to build a custom plan type.

2. Oracle EPM Cloud, Administering Planning, Chapter 2: Creating a Custom Application: This chapter details the process of building applications from scratch. It implicitly supports the rationale for option B by explaining that custom applications (and plan types) allow for complete control over the dimensionality, which is necessary when pre-built modules are too restrictive.

3. Oracle Essbase 21c, Database Administrator's Guide, Chapter 1: Oracle Essbase Overview, "Block Storage Cubes vs. Aggregate Storage Cubes": This foundational document explains the architectural differences between BSO and ASO. It clarifies that BSO is for complex calculations but can face performance challenges with large, sparse dimensions. ASO is designed for fast aggregation on large, sparse data sets. This supports the reasoning that building another BSO cube (Option E) is not the correct solution for BSO aggregation performance issues.