CloudWatch log groups were created with no expiration. A policy now requires application logs to be retained for 90 days, while new events must continue to arrive normally. Which action should operations take?

1. Set each applicable log group retention policy to 90 days.
2. Delete and recreate every log stream each night.
3. Export logs to S3 and configure a 90-day S3 lifecycle policy without changing the source log groups.
4. Set the metric alarm evaluation period to 90 days for each log-derived metric.