The application of which principle helps to define what should be included in a project?

The application of the "Continued Business Justification" principle in PRINCE2® helps to define what should be included in a project. This principle ensures that a project remains viable and relevant, with a clear justification for starting and continuing each stage of the project. It supports decision-making about the inclusion of specific components or activities based on their contribution to project objectives and expected benefits. References: PRINCE2® Foundation Handbook, Continued Business Justification section.