PCA (Prometheus Certified Associate) sample exam question with answer 403

Question:
Which of the following functions can be used to calculate the standard deviation of a metric? (Select all that apply)

1. stddev()
2. stdvar()
3. stdev()
4. var()

Answer:
A, B - correct answers. The stddev() and stdvar() functions can be used to calculate the standard deviation and variance of a metric, respectively
C - stdev() function is not a valid function in PromQL
D - var() function calculates the variance, not the standard deviation