PCA (Prometheus Certified Associate) sample exam question with answer 567

Question:
Let job node designate a Node Exporter scrape with instances node1, node2 and node3.
Which of the following queries selects the value of the up metric for job node and instance node1?

1. SELECT up FROM tsdb WHERE job="node" and target="node1"
2. up{job="node", instance="node1"}
3. up{job="node" instance="node1"}
4. SELECT up FROM tsdb WHERE job="node" and instance="node1"

Answer:
B - is the correct answer. More at instant-vector-selectors
A, D - are incorrect as these queries are written in SQL syntax whereas Prometheus has a custom query language called PromQL with a completely different syntax
C - is incorrect as this query is missing a comma between the two label selectors