How many User Roles can be assigned to a single user?

The correct choice is that a single user can be assigned one User Role. In the context of Marketing Cloud, User Roles are designed to provide specific permissions and access levels based on the responsibilities of the users. Each role encompasses a set of permissions that controls what actions the user can take within the platform.

Assigning only one role per user ensures that the permissions are clear and manageable, preventing potential confusion that could arise from having multiple roles overlapping with differing levels of access. This structure maintains a secure and structured environment, ensuring users have access only to the tools and data relevant to their tasks.

The other options imply multiple roles could be assigned, which could lead to complications in defining user capabilities and responsibilities, reducing the clarity and security of the user management system within the platform.