PCA (Prometheus Certified Associate) sample exam question with answer 458

Question:
As far as alert metadata goes, would "alert description" be more appropriate as a label or an annotation?

1. Neither one would be acceptable
2. Label
3. Either one would be acceptable
4. Annotation

Answer:
D - is correct. More at defining-alerting-rules
A - is incorrect as an annotation is perfect for that type of alert metadata
B - is incorrect as "alert description" is longer-form metadata which is perfect as an annotation. Labels should be used only for metadata that uniquely identifies an alert such as its name, the environment and data center from where it originated, etc.
C - as incorrect as "alert description" would not be an appropriate label