PCA (Prometheus Certified Associate) sample exam question with answer 232

Question:
Let cert_expiry be a gauge metric whose value is a Unix timestamp (epoch time) representing the time a given certificate will expire. Assume this metric is being monitored for several instances.
Which of the following queries yields the expiration time (as a Unix timestamp) of the FIRST certificate expiration?

1. max(cert_expiry)
2. min(timestamp(cert_expiry))
3. min(cert_expiry)
4. max(timestamp(cert_expiry))

Answer:
C - is the correct answer
A - this query yields the last certification expiration time, not the first
B, D - is incorrect as the timestamp function provides the Unix timestamp of when a given sample was collected, not the timestamp of the certificate expiration. The raw metric cert_expiry already provides the necessary certificate expiration timestamp