The authorization to deliver the project's products is given during the Directing a Project process. This process involves the Project Board's decision-making responsibilities, including granting permission to proceed with the project after the initiation phase and authorizing the delivery of stages as the project progresses. References: PRINCE2 Foundation manual, PRINCE2 official resources

The risk response type "Transfer" is applicable to both threats and opportunities. This response involves transferring the ownership of the risk to a third party who is better able to manage the risk, thus applying to both positive and negative risks. References: PRINCE2 Foundation Training Manual; PRINCE2 2017 Foundation handbook.

To monitor the progress of a stage effectively, the project manager should review both the Highlight Report and Checkpoint Report. The Highlight Report provides a summary of the stage status to the Project Board, detailing overall progress and identifying any major issues. The Checkpoint Report, on the other hand, offers detailed updates from team managers or team members on the progress of their respective Work Packages.
Together, these management products give a comprehensive view of stage progress.References: (PRINCE2
7 Foundation Handbook, AXELOS)

The purpose of the 'managing product delivery' process in PRINCE2 is to control the link between the project manager and the team managers. This process ensures that the work on products meets the requirements specified by the project and is agreed upon between the project manager and the team manager, focusing on the acceptance, execution, and delivery of work packages.References: PRINCE2 7 Foundation materials on the 'managing product delivery' process.