The best action for the Scrum Master to take in this situation is to conduct a session to help the Scrum Team resolve the conflict and create a uniform Definition of Done. This is because the Scrum Master is a servant-leader, a facilitator, and a coach to the team, who should have the skills to help resolve conflicts if called upon by the team. The Scrum Master can employ various strategies to effectively resolve conflicts within the Scrum Team, such as promoting open communication, facilitating active listening, mediating disagreements, and fostering collaboration.
The Scrum Master can also remind the team members that conflicting ideas are natural and can be beneficial for innovation and learning, but making it personal does not help and violates the Scrum values of respect and openness. The Scrum Master can guide the team to create a clear and shared Definition of Done that reflects their quality standards and expectations for the product4.

Sprints promote iterative and incremental development.

The Scrum Team and its stakeholders agree to be open about all the work and the challenges with performing the work.

Explanation/Reference:
Explanation:
The Product Owner's primary concern is the flow of value reflected in the ordering of the Product Backlog.