Socket Mode enables a Slack application to receive Events API payloads and interactive events over a WebSocket connection instead of exposing a publicly accessible HTTP Request URL. Slack's current documentation explicitly states that the WebSocket URL is not static. The application obtains the URL at runtime by invoking apps.connections.open, and Slack refreshes that URL periodically. This architecture is particularly useful for applications operating behind corporate firewalls, during local development, or in environments where exposing an inbound public HTTP endpoint is undesirable. Therefore, B precisely matches Slack's documented description: the application listens through a non-static WebSocket URL dynamically created while the application is running. There is, however, a defect in the supplied question: C is semantically equivalent to B. Slack itself uses the wording “created at runtime,” so C also describes the underlying behavior accurately. Because this is marked as a single-choice question, B should be retained as the intended exam answer, but the alternatives are not sufficiently differentiated to make B uniquely true. This belongs to Tools, particularly Socket Mode, WebSockets, apps.connections.open, and alternative event-delivery architecture.