PCA (Prometheus Certified Associate) sample exam question with answer 501

Question:
Which of the following PromQL expressions would give the number of requests served by a specific server in the last 5 minutes?

1. sum(requests_served{server="my-server"}[5m])
2. delta(requests_served{server="my-server"}[5m])
3. rate(requests_served{server="my-server"}[5m])
4. count(requests_served{server="my-server"}[5m])

Answer:
A - is the correct answer. The sum aggregation function is used to add up all the values in the input range vector. In this case, we want to sum up the number of requests served by a specific server in the last 5 minutes