Final answer:
In Blanchard and Fabrycki's model, the project scope is developed by the customer organisation in negotiation with the producer organization, ensuring that the needs of customers and stakeholders are met.
Step-by-step explanation:
In Blanchard and Fabrycki's model for the interaction of different organizations at the beginning of a Systems Engineering Process, it is typically the customer organization that develops the project scope. This happens through negotiations with the producer organization. The scope includes all aspects of what the project is expected to achieve and outlines the expectations and requirements to satisfy the needs of the customer and stakeholders.
Stakeholders can include a variety of parties such as government agencies, companies, and individuals, all of whom have an interest in the product. Understanding the roles of these different entities is critical for the successful initiation of any systems engineering project. Hence, option (a) 'The customer organization in negotiation with the producer organization' is the correct choice.