PCA (Prometheus Certified Associate) sample exam question with answer 485

Question:
Let job="node" represent a Node Exporter scrape.
Which of the following queries gives the timestamp of the last scrape for each of the instances of the node job?

1. last_scrape_timestamp{job="node"}
2. timestamp(up{job="node"})
3. time({job="node"})
4. last_scrape_time{job="node"}

Answer:
B - is corect answer. More at timestamp
A, D - are incorrect as these are not the metrics exposed by Prometheus when scrapes are performed
C - is incorrect as the time function yields the current time as a Unix timestamp and does not accept any arguments