Roles that Cannot be Combined

C.

In PRINCE2 (PRojects IN Controlled Environments), a project management methodology widely used in the UK and around the world, each role has specific responsibilities and accountabilities. Combining certain roles may create conflicts of interest and potentially compromise the project's success.

Let's go through each of the options:

A. Executive and Senior User: Combining the roles of Executive and Senior User is possible, but it is not recommended. The Executive is responsible for ensuring that the project's objectives are aligned with the organization's strategy and business case, while the Senior User represents the end-users or customers and ensures that their needs are met. Combining these roles may create conflicts of interest between the organization's strategy and the end-users' needs, making it challenging to balance both.

B. Project Manager and Project Support: Combining the roles of Project Manager and Project Support is also possible, but it is not recommended. The Project Manager is responsible for the overall management of the project, while the Project Support provides administrative and logistical support to the project team. Combining these roles may create conflicts of interest, as the Project Manager may be tempted to focus on administrative tasks rather than managing the project's progress.

C. Project Assurance and Team Manager: Combining the roles of Project Assurance and Team Manager is not recommended. Project Assurance is responsible for reviewing the project's progress and ensuring that it is following the PRINCE2 methodology, while the Team Manager is responsible for managing the project team's day-to-day activities. Combining these roles may create conflicts of interest, as the Team Manager may feel that their authority is being challenged by Project Assurance, potentially leading to communication breakdowns.

D. Senior Supplier and Supplier Assurance: Combining the roles of Senior Supplier and Supplier Assurance is not recommended. Senior Supplier is responsible for managing the supplier(s) providing goods and services to the project, while Supplier Assurance is responsible for ensuring that the supplier(s) are delivering quality products and services. Combining these roles may create conflicts of interest, as the Senior Supplier may be more concerned with meeting their own interests rather than ensuring that the supplier(s) are delivering quality products and services.

Therefore, the role that cannot be combined is D, Senior Supplier and Supplier Assurance.