PCA (Prometheus Certified Associate) sample exam question with answer 391

Question:
Which of the following functions is NOT appropriate for use with counter metrics?

1. idelta
2. resets
3. irate
4. increase

Answer:
A - is the correct answer. The idelta function is only appropriate for use with gauge metrics. More info at idelta
B, C, D - are incorrect as these functions are appropriate for use with counter metrics