Which statements are correct concerning the use of service composition within the ServiceOriented Integration architecture?

Service composition is the creating of a new SOA Service by aggregating existing SOA Services.
Which statements are correct concerning the use of service composition within the ServiceOriented Integration architecture?

A.
The SOI architecture is a layered architecture; therefore service composition is not allowed.

B.
Service composition is allowed, even encouraged, by the SOI architecture.

C.
Service composition within the SOI architecture is allowed only when the aggregation is over
SOA Services from lower layers in the architecture.

D.
Service composition should be avoided because service aggregation is provided by the
Mediation Layer.

E.
Service composition is allowed, but is discouraged because service composition leads to
complex dependencies.

Explanation:
Service composition is the ability to leverage lower-level services to create a
higher-level service
When doing composition, the developer should respect the layering of the
architecture. Thus, a Business Service could leverage existing Connectivity Services or
Data Services and a Data Service could leverage existing Connectivity Services. But, a
Data Service should not call a Business Service and a Connectivity Service should not
call a Data Service or a Business Service
Reference: Oracle Reference Architecture, Service-Oriented Integration, Release 3.0