PCA (Prometheus Certified Associate) sample exam question with answer 122

Question:
How can the count of observations in each bucket of a histogram be queried in PromQL?

1. Using the sum function
2. Using the count function
3. Using the histogram function
4. Using the histogram_quantile function

Answer:
B - The count function in PromQL returns the number of samples in the range vector. When applied to a histogram metric, it returns the count of observations in each bucket