A SOAP extensions enable developers to modify the request or response streams of SOAP messages
B SOAP extensions are applied to a particular operation with a custom SOAP extension attribute, or registered with the application (or machine) configuration file
C Description formatters can be created to add custom WSDL extensions, and then read to add these SOAP extension attributes
D HTTP modules and custom Web requests can be used only for a lower level extensibility
E The Web Services Management for Microsoft .NET (WSM) can enhance .NET Web Services for various Web service protocols that extend beyond the baseline, such as WS-Attachments and WS-Security
F All of these