A database administrator needs to create a federated database and configure access to join data
from 3 Oracle instances, 2 SQL Server instances, and 1 DB2 database. Which objects are needed
to establish the specified connections?

A.
3 Oracle servers, 1 Oracle wrapper, 2 SQL Server servers, 1 SQL Server wrapper, and
nicknames for all databases.

B.
3 Oracle servers, 3 Oracle wrappers, 2 SQL Server servers, 2 SQL Server wrappers, and
nicknames for all databases.

C.
3 Oracle servers, 1 Oracle wrapper, 2 SQL Server servers, 1 SQL Server wrapper, 1 DB2
server, 1 DB2 wrapper, and nicknames for alldatabases.

D.
3 Oracle servers, 3 Oracle wrappers, 2 SQL Server servers, 2 SQL Server wrappers, 1 DB2
server, 1 DB2 wrapper, and nicknames for alldatabases.

Explanation: