PCA (Prometheus Certified Associate) sample exam question with answer 325

Question:
With the following alertmanager configs, after a notification has been sent out for the group severity: critical, an new alert for that group comes in. How long will alertmanager wait before firing a new notification?

route:
  receiver: staff
  group_by: ['severity']
  group_wait: 60s
  group_interval: 15m
  repeat_interval: 12h
  routes:
    - matches:
        job: kubernetes
      receiver: infra
      group_by: ['severity']
  1. 12hr
  2. 4y
  3. 60s
  4. 15m
  5. 80ms
  6. 5m
Answer:
D - correct answer