A hospital alarm already emails the on-call list from one SNS topic. The same alarm must also POST to the paging vendor's HTTPS endpoint. A teammate wants a second alarm with the same threshold. What should be added?
Select an answer to reveal the explanation.
Short Explanation
One bell can ring in two rooms if both rooms are wired to it. You already have the alarm and the topic, so the pager is another subscription on that topic, not a second alarm that will drift out of sync. A trail watches API calls, and an email endpoint does not speak HTTPS to a vendor.
Full Explanation
SNS fan-out is the point of a topic. The alarm publishes once to the topic it already uses, and each subscription receives a copy. Adding an HTTPS subscription delivers the same state change to the paging endpoint while the existing email subscriptions keep working. A second alarm with the same threshold creates two independent evaluation paths that will be edited separately and can page twice or page differently. CloudTrail records API calls and delivers log files. It does not evaluate the metric and it does not replace an alarm action. A VPC endpoint provides private connectivity to an AWS service. It does not add a notification channel to an alarm. Caveat: an HTTPS subscriber must confirm the subscription, and a pending HTTPS subscription stays silent the same way an unconfirmed email does. Operational check: publish a test notification to the topic and confirm both the mailbox and the paging endpoint received that single publish.