A team stores database passwords in Key Vault. The application must handle Key Vault throttling gracefully. Which HTTP status code indicates throttling?

1. A 401 Unauthorized
2. B 403 Forbidden
3. ✓ C 429 Too Many Requests (correct answer)
4. D 503 Service Unavailable

Shortcut: Key Vault returns HTTP 429 when the request rate exceeds the vault's throttle limits. Implement exponential backoff retry logic and Retry-After header handling in the application.