You create an application by using Microsoft Visual Studio .NET 2008 and the .NET Framework 3.5.
The application includes a set of Windows Communication Foundation (WCF) services to authorize and settle credit card transactions.
A separate service is implemented for each credit card provider. However, the same service contracts and data contracts are used across all implementations.
The incoming requests to the service must conform to the contracts.
You need to implement validation to meet the requirement by using a minimum amount of development effort.
What should you do?

A.
Use the CustomValidator class.

B.
Inspect input parameters directly in the service method.

C.
Implement the IDispatchMessageInspector interface.

D.
Implement a custom class that inherits from the SoapExtension class.