23题：choose one

Which statement is true about the Database as a Service (DBaaS) instances and Database instances in Oracle Public Cloud?

A) An Oracle database instance can support only one DBaaS instance.

B) A DBaaS instance can support multiple Oracle database instances.

C) An Oracle database instance can support multiple DBaaS instances.

D) A DBaaS instance runs in a pluggable database (PDB), which is contained in a multi-tenant container database (CDB).

E) A DBaaS instance can support only one Oracle database instance.

Answer：B

(解析：虽然没有用过DBaaS，但是从原理角度分析，应该是一对多的关系，要不然统一管理就失去意义了。)