What are the roles within a scrum methodology?

'Retirements manager' is not a role that exists in Scrum or any standard project management methodology, making this option fabricated and incorrect.

'System owner' is not a defined Scrum role; while a 'Product Owner' exists in Scrum, 'System owner' is a term more associated with IT governance and security frameworks like FISMA, not Scrum.

While a 'Scrum Master' is a valid role, 'quality assurance team' is not a distinct Scrum role - QA responsibilities are embedded within the cross-functional Scrum Team, and 'scrum team' alone without 'Product Owner' omits a critical role.

The three official Scrum roles as defined by the Scrum Guide are the Product Owner (responsible for maximizing product value and managing the backlog), the Scrum Master (responsible for facilitating the process and removing impediments), and the Scrum Team (the cross-functional group that delivers the product increments). These are the only formal roles recognized within the Scrum framework.