What are the roles within a scrum methodoligy?

'System Owner' is not a defined role in Scrum methodology; the correct counterpart is 'Product Owner,' making this answer technically inaccurate.

The three official roles in Scrum are the Product Owner (responsible for managing the product backlog and stakeholder communication), the Scrum Master (responsible for facilitating the Scrum process and removing impediments), and the Scrum Team (the cross-functional group that delivers the product increment). These roles are defined by the official Scrum Guide authored by Ken Schwaber and Jeff Sutherland, the creators of Scrum.

'Requirements Manager' is not a Scrum role; Scrum intentionally avoids traditional project management titles, and the responsibility for requirements is handled by the Product Owner.

While 'Scrum Team' is a valid Scrum role, 'Quality Assurance Team' is not a distinct Scrum role - QA responsibilities are embedded within the cross-functional Scrum Team itself, and the 'Product Owner' is missing entirely from this option.