Answer:
Product owner(s), product
Step-by-step explanation:
Under normal circumstances, maintenance of product backlog is done when there are multiple teams working on independent products. Each unique combination of team and product should have an independent Product Backlog. At any given time, the product owner(s) can add or remove features from the product backlog. It's important to note that whenever there's new information learned, the product owner should re-prioritize the product backlog.