单选题
The software architecture of a program or computing system
is the structure or structures of the system, which comprise software ______,
the externally ______ properties of those components, and the relationships
between them. The architecture is not the operational SOftware. Rather, it is a
______ that enables a software engineer to: analyze the ______ of the design in
meeting its stated requirements, consider architectural alternatives at a stage
when making design changes is still relatively easy, and reduce the ______
associated with the construction of the software.