TL;DR
In general, a Product Owner should focus on process, not on technical solutions. Your role on a Scrum Team is to represent the stakeholders or users, and to drive the development of the product, rather than to manage implementation details.
The Product Backlog it a set of high-level deliverables, not a set of specification documents. Don't get caught in the trap of treating user stories or Product Backlog Items as specification documents, or attempting to drive implementation-level details which are the responsibility of the Development Team.
Focus on Process
The Product Owner's job is to work with stakeholders to gather requirements, and with the team to refine user stories. Whether in an interview or in an active role, I'd focus on the methodologies used to gather requirements and build consensus; leave the technical solution alone unless you're specifically being hired for your UX expertise.
Example Process: Theme Screening
For example, you might talk about how you would use a tool like Theme Screening to quickly build consensus about what Product Backlog Items (PBIs) should be prioritized for the project. Consider the following:
In this example, stakeholders should be able to easily compare the relative merits of the Baseline, Embiggening, and Ensmallening themes/epics against one another. Given the right selection criteria, your stakeholders should quickly develop consensus around spending available project resources on the highly-ranked Embiggening theme, and on all the user stories that collectively compose it.
Later on, you will refine whether your Baseline or Ensmallening themes are more important by repeating this process as the project progresses and the Cone of Uncertainty narrows. Stakeholder input should be just as iterative as the product development itself, so this type of ranking process should be an expected practice when a project needs to establish relative rankings for its deliverables.
