It is D (15.4.3)

During the "Initiating a Project" process, the detailed planning of the project is conducted, which includes setting up the project controls and tolerances. This process involves defining the project's scope, objectives, and how it will be controlled and governed. Part of this involves setting the tolerances for each stage, which are agreed upon to ensure that the project stays on track and within acceptable limits. The other options are not correct because: A. Controlling a Stage: This process involves managing and monitoring the day-to-day activities within a stage, not setting tolerances. C. Managing a Stage Boundary: This process is about reviewing the current stage and planning for the next stage, but the tolerances would already have been set during the initiation. D. Directing a Project: This process is about the Project Board providing overall direction and decision-making but not specifically about setting stage tolerances. Thus, stage tolerances are established during the "Initiating a Project" process to provide clear guidelines for project execution and control.

I would also say D as it asked for PHASE tolerences.

Stage tolerances are set by Project Board under the 'Directing a Project' process. (refer 15.4.3)

B During the "Initiating a Project" process, one of the key activities is to define the project controls, including the setting of tolerances.

It is "B". Ref 16.4.6 Set up the project controls