The Product Owner is a singular, critical role in Scrum: "The Product Owner is one person, not a committee." Temporary or permanent unavailability requires specific actions:
* A:During a Sprint, the Developers' self-management allows them to proceed toward the Sprint Goal, adjusting with the Product Owner later, per: "The Developers are self-managing, meaning they internally decide who does what, when, and how."
* C:Permanent absence means Scrum isn't being followed without a Product Owner, necessitating a replacement: "For Product Owners to succeed, the entire organization must respect their decisions."