Product Owner attendance at the Nexus Sprint Review

While preparing to take the Scaled Professional Scrum exam, I noticed something peculiar about the stated attendees of the Nexus Sprint Review. The Nexus Guide says:

The Nexus Sprint Review is held at the end of the Sprint to provide feedback on the Integrated Increment that a Nexus has built over the Sprint. All individual Scrum Teams meet with stakeholders to review the Integrated Increment. Adjustments may be made to the Product Backlog.

I found it odd that the guide does not explicitly state that the Product Owner attends the Nexus Sprint Review--only stakeholders and  "all individual Scrum Teams." Shouldn't the Product Owner always attend? I pondered the question for a while, and summarized thinking into three possible explanations:

1. The Product Owner isn't needed at the Nexus Sprint Review. This explanation seems preposterous. As a result of the Review, "Adjustments may be made to the Product Backlog." Since the Nexus Guide also states that, "The Product Owner is accountable for the Product Backlog, including its content, availability, and ordering," it seems logical that the Product Owner should attend the Nexus Sprint Review.
2. The Product Owner isn't explicitly mentioned as an attendee because the Product Owner is essentially the primary stakeholder for the product being created by the Nexus and, as such, is included in the Nexus Sprint Review under the umbrella of "stakeholders." I find this explanation unsatisfactory. It implies a lack of precision of language that I don't see anywhere else in the Scrum Guide or the Nexus Guide. The Scrum Guide always distinguishes the stakeholders from the Scrum Team and, by extension, from the Product Owner. For the Nexus Guide to blur that line seems unlikely.
3. The Product Owner isn't explicitly mentioned as an attendee because Nexus uses Scrum as its building block. In the Scrum Guide, it states that "During the Sprint Review, the Scrum Team and stakeholders collaborate about what was done in the Sprint." The Product Owner is included as a member of the Scrum Team in single-team Scrum. By extension, although the Product Owner is not a member of any specific Scrum Team in a Nexus, the Product Owner is an implicit member of every Scrum Team in a Nexus, and is therefore included in the Nexus Sprint Review as an implicit member of " All individual Scrum Teams." I find this explanation more satisfying than the last because it is easily derived from what is stated in both the Nexus Guide and the Scrum Guide, without any need to blur or shade meaning anywhere.

I'm curious to know what others think about this question.