题目内容：
An architectural Style defines as a family of such systems in terms of a （请作答此空）of structural organization. More specifically an architectural style defines a vocabulary of（ ） and connector types, and a set of（ ）on how they can be combined. For many styles there may also exist one or more （ ） that specify how to determine a system's overall properties from the properties of its parts. Many of architectural styles have been developed over the years. The best-known examples of （ ）architectures are programs written in the Unix shell．
A.pattern
B.data flow
C.business process
D.position level
参考答案：