The Product Backlog is an ordered list of what is needed to improve the product, and it is the single source of work undertaken by the Scrum Team. The Product Owner is responsible for ordering the Product Backlog items by value, risk, priority, and dependencies. The Product Backlog should be transparent and accessible to the Scrum Team and the stakeholders, so that everyone can understand the scope and progress of the product development. Therefore, options A and B are true statements about the Product Backlog.
Option C is not true because the Product Backlog items can be expressed in various formats, such as user stories, use cases, scenarios, or any other way that clearly conveys the intent and value of the item. User stories are a common and useful technique, but not a mandatory one.
Option D is not true because the Product Backlog is not a fixed and complete specification of the product, but rather an emergent and dynamic artifact that evolves over time. The Product Backlog items are refined and clarified by the Product Owner and the Developers throughout the product development process, and new items can be added or removed as needed. The Product Backlog does not need to be fully defined before the first Sprint begins, but only enough to support the first Sprint Planning.
Option E is not true because the Product Owner is not the only source of ideas and requirements for the product. The Product Owner collaborates with the Developers and the stakeholders to discover, validate, and prioritize the Product Backlog items. The Product Owner may delegate the authority to add items to the Product Backlog to others, but remains accountable for the ordering and the value of the Product Backlog.
Option F is not true because the Product Backlog does not replace the communication and collaboration between the Developers and the stakeholders. The Product Backlog represents the input of all stakeholders, but it is not a substitute for direct feedback and interaction. The Developers need to engage with the stakeholders to understand their needs, expectations, and feedback, and to deliver a valuable product increment that meets the Sprint Goal and the Definition of Done. References:
Professional Scrum Product Owner II Assessment
Understanding and Applying the Scrum Framework
Managing Products with Agility
[What is a Product Backlog?]
[Product Backlog Explained]

Explanation
According to the Professional Scrum Product Owner™ II certification guide1, the Definition of Done is a formal description of the state of the Increment when it meets the quality measures required for the product.
The Definition of Done creates transparency by providing everyone a shared understanding of what work was completed and what standards were met as part of the Increment. If the Definition of Done is not met, the Increment is not Done and cannot be released. Therefore, the following statements are true:
* A. The next Sprint may be interrupted when quality issues are encountered. This is true because the Scrum Team may have to spend time fixing the quality issues in the previous Increment before working on the new Sprint Backlog items. This may affect the Sprint Goal and the delivery of value.
* C. The indication of progress on the Product Backlog is not transparent. This is true because the Product Backlog items that were supposedly Done in the previous Sprint are actually not Done according to the Definition of Done. This means that the Product Owner cannot accurately forecast the release plan and the stakeholders cannot trust the progress reports.
* D. The Scrum Team should not release the Increment. This is true because releasing an Increment that does not meet the Definition of Done may compromise the quality, usability, and value of the product. It may also damage the reputation and trust of the Scrum Team and the organization.
* E. The incomplete Sprint Backlog items should be returned to the Product Backlog. This is true because the Sprint Backlog items that were not Done according to the Definition ofDone are still part of the Product Backlog. The Product Owner should re-order them based on their value and priority and decide when to include them in the next Sprint.
The following statement is false:
* B. The project manager cannot effectively update the plan. This is false because there is no project manager role in Scrum. The Product Owner is responsible for managing the Product Backlog and the value delivery, while the Scrum Master is responsible for facilitating the Scrum process and removing impediments. The Developers are responsible for managing the Sprint Backlog and the quality of the Increment.
References: 1: Professional Scrum Product Owner™ II Certification | Scrum.org