The mssparkutils.notebook.runMultiple() method is used to execute multiple notebooks, which can be structured as a Directed Acyclic Graph (DAG). To establish the required execution order where Load_Orders runs only after Load_Salesperson completes, you must define this relationship within the JSON configuration.

1. dependencies: This key is used within an activity's definition (in this case, Load_Orders) to specify an array of prerequisite activities (by name) that must complete successfully before this activity can begin.
2. runMultiple: This is the specific method within the mssparkutils.notebook utility that parses the JSON DAG and orchestrates the parallel and sequential execution of the defined notebook activities.

Source: Microsoft Learn (Official Vendor Documentation)

Article: Use Microsoft Spark utilities (mssparkutils) in Fabric

Section: mssparkutils.notebook.runMultiple(DAG)

Reference: The official documentation explicitly shows the runMultiple method is used to "run multiple notebooks in parallel or with a predefined topological structure (DAG)." The accompanying example code demonstrates that the dependencies key is used within the activities JSON array to define the execution order between notebooks. For instance, an activity "NotebookSimple2" is shown with "dependencies": ["NotebookSimple"] to make it run after "NotebookSimple". This directly validates the answer.