Microsoft's COM is a software（1）that allows applications to be built from binary software components. COM is the underlying architecture that forms the foundation for higher-level software services, like those provided by OLE.COM defines a binary standard for function calling between components,a way for components to dynamically discover the interfaces implemented by other components,and a mechanism to identify components and their interfaces uniquely. OLE is a compound（2）standard developed by Microsoft.OLE makes it possible to create（3）with one application and link or embed them in a second application.Embedded objects retain their original format and（4）to the application that created them.Support for OLE is built into the Windows and MacOS Operating Systems.A（5）compound document standard developed mainly by Apple and IBM is called OpenDoC. 空白（5）处应选择（）

• A、completing
• B、competing
• C、connecting
• D、contained