PCA (Prometheus Certified Associate) sample exam question with answer 194

Question:
Which query below will give the active bytes on instance 10.1.1.1:9100 45m ago?

1. node_memory_Active_bytes offset 45m
2. node_memory_Active_bytes{instance="10.1.1.1:9100"} offset 45m
3. node_memory_Active_bytes{instance="10.1.1.1:9100"}[45]
4. node_memory_Active_bytes{instance="10.1.1.1:9100"} @45m

Answer:
B - is the correct answer