※This sample exam is different from those that appear in the actual OSS-DB Exam.
The database storage area of PostgreSQL contains multiple databases, which are called database clusters. Please note that it does not relate to clustering technology used for high availability.
Immediately after creating the database cluster with the Initdb command, three databases, template0, template1, and postgres, are included.
Since one database cluster is managed by the same server process, multiple databases in the cluster use the same version of PostgreSQL.
It is also possible to create multiple database clusters on one server. In order to run multiple versions of PostgreSQL on a single server, you need to create a separate database cluster for each version.
Therefore, the correct answer is B.