PCA (Prometheus Certified Associate) sample exam question with answer 399

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 different instances.
Which of the following queries yields the time in days until the LAST certificate expiration?

1. min(cert_expiry – time())
2. max(cert_expiry - time())
3. max(cert_expiry - time()) / 86400
4. min(cert_expiry - time()) / 86400

Answer:
C - correct answer
A - is incorrect as this query gives the time in seconds until the first certificate expiration, not the time in days until the last
B - is incorrect as this query gives the time in seconds until the last certificate expiration, not the time in days as requested by the question. To convert to days it is necessary to divide the result by 86400 (86,400 seconds in a day)
D - is incorrect as this query gives the time in days until the first certificate expiration, not the last