The primary role of the Product Owner in Disciplined Agile is to "build the right product." This means the Product Owner is responsible for defining and prioritizing the product backlog, ensuring that the development team works on features that deliver the most value to the stakeholders and align with the business objectives. The Product Owner acts as the voice of the customer, making critical decisions about the product's direction, features, and functionality. The other options (B, C, and D) may involve activities related to product development, but they do not encompass the core responsibility of building the right product.