What is the least suitable method to document the details of a single use case?

The least suitable method for documenting the details of a single use case is the context diagram. Context diagrams primarily provide a high-level view of the system's boundaries, interactions, and relationships with external entities. They illustrate how the system interfaces with these external actors and do not delve into the specific behaviors or steps involved in a particular use case.

In contrast, state diagrams and activity diagrams are effective for modeling the dynamic aspects and workflows within a use case. State diagrams focus on representing the states that an object passes through and the transitions caused by events, while activity diagrams provide a more detailed view of the flow of activities and tasks within a use case.

Using natural language is another common method for documenting use cases, as it enables clear and understandable descriptions that can capture nuances, exceptions, and detailed requirements effectively.

Overall, the context diagram lacks the granularity needed to document the intricate details of a specific use case, making it the least suitable option in this scenario.