PCA (Prometheus Certified Associate) sample exam question with answer 573

Question:
Which of the following quote types are NOT valid to use in Prometheus query expressions?

1. `
2. “
3. '
4. "

Answer:
B - is the correct answer. More at string-literals
A - is incorrect as backticks are valid in PromQL. They also have the special benefit of avoiding extra escape sequences when working with regular expressions
C - is incorrect as single quotes are valid in PromQL
D - is incorrect as double quotes are valid in PromQL