Step 2 of your process involves calling an external Weather API. Ideally, the API works, but sometimes it fails with a '503 Service Unavailable'. What is the best simple strategy to handle this?

1. A Retry immediately and repeatedly in a tight loop.
2. B Retry a few times with 'Exponential Backoff' (wait longer between each try).
3. C Crash the application.
4. D Return '200 OK' to the user but with empty data.