Which operation contract should you create?

You are creating a Windows Communication Foundation (WCF) service by using Microsoft .NET Framework 3.5.
You Configure a binding to enable streaming.
You need to ensure that the client application is able to stream large XML files to the WCF service.
Which operation contract should you create?

A.
[OperationContract]
void UploadFile(Stream xmlData);

B.
[OperationContract]
void UploadFile(XmlWriter xmlData);

C.
[OperationContract]
void UploadFile(StreamWriter xmlData);

D.
[OperationContract]
void UploadFile(byte[] xmlData);