You implement Azure Durable Functions for a vehicle loan workflow that requires multiple steps in sequence and includes a credit-check step that can take several days. Which Durable Function type is appropriate for this workflow?

An orchestrator function is the correct choice because it defines the workflow logic, managing the state and execution of other Durable Functions (activity, entity, or sub-orchestrator functions). For a multi-step, long-running process like a vehicle loan workflow with a potentially multi-day credit check, an orchestrator function can reliably coordinate the sequence of steps, handle retries, and manage the overall state without losing progress, even if the underlying infrastructure experiences issues. Client functions are used to start orchestrator functions. Activity functions perform the actual work within an orchestration. Entity functions are used for managing stateful entities.