Section: Volume B
Explanation/Reference: http://prince2.wiki/Manage_by_stages

The level of tailoring in PRINCE2 should be defined during the initiation stage of the project. This stage involves setting up the proper foundation for the project by adapting the method to suit the project's environment, including deciding how much and which parts of the methodology to apply. References:
PRINCE2 Foundation Handbook, Tailoring PRINCE2 section.

According to the 'continued business justification' principle in PRINCE2, project benefits must be aligned to the business objectives. This alignment ensures that the project remains viable and relevant throughout its life cycle, and that it contributes to achieving strategic goals. References: PRINCE2 Foundation Training Manual; PRINCE2 2017 Foundation handbook.