Which statement is true about clustering key?

Which statement is true about clustering key?
A . Clustering key can be one per table but the key can have more than one column
B. Clustering key can be many per table and each key can have more than one column
C. Clustering key can be many per table but each key can have only one column

Answer: A

Explanation:

Clustering physically sorts the data, which means we can have only one key per table but with possible sub-keys. So, choose your cluster key wisely. You should choose the key that appears frequently in your selective query(where clause), also keys which are used in JOIN predicates are good candidates for becoming a cluster key.