PCA (Prometheus Certified Associate) sample exam question with answer 563

Question:
Which of the following queries will return the currently firing alerts in Prometheus?

1. ALERTS{alertstate="firing"}
2. No such query exists
3. ALERTS{alertstate="firing",location="prometheus"}
4. ALERTS

Answer:
A - is the correct answer. More at inspecting-alerts-during-runtime
B - is incorrect as such a query does exist
C - is incorrect as there is no built-in label location for the ALERTS metric that distinguishes where the alerts are firing. The synthetic ALERTS metric only gives the alerts as evaluated by Prometheus, it does not provide alerts as seen in Alertmanager
D - is incorrect as this query will also return pending (not yet firing) alerts