Which PRINCE2 principle is being applied when tolerances are set for the three levels of plan?

Identify the missing word in the following sentence. The guiding obligations and good practices which determine whether the project is genuinely being managed using PRINCE2 form the [ ? ] of the method.

Which project management team member represents the interest of those who will operate the project's products to realize the benefits after the project is complete?

Which is a typical core activity within configuration management?

Which is part of quality control?