Which of the following would be the most appropriate use-case for a Function as a Service (FaaS) implementation?

FaaS functions are typically stateless and have ephemeral storage, making them unsuitable for applications that require a persistent local file system.

FaaS is not ideal for applications that continuously poll for work, as this would keep the function 'warm' and incur continuous costs, negating the serverless cost-efficiency model.

FaaS platforms are designed for serverless execution of short-lived, stateless functions that respond to events, automatically scaling resources up or down based on demand. This makes them ideal for event-driven architectures where costs are optimized by paying only for actual computation time.

While FaaS functions can interact with distributed storage services, the FaaS itself does not natively provide a globally-distributed file system; such storage would be a separate, integrated service.