or performing threat modeling for an application, especially when using the Microsoft Threat Modeling Tool, you should create:

B. Data Flow Diagram (DFD)

Data flow diagrams are the primary choice for threat modeling as they help in visualizing how data moves through the system, where it is stored, and how it is processed. This allows you to identify potential security vulnerabilities related to data handling, access points, and data storage. The Microsoft Threat Modeling Tool is particularly geared towards analyzing data flow diagrams to identify potential threats.