A Windows Communication Foundation (WCF) service is generating a separate namespace declaration for each body member of a message contract,even though all body members share the same namespace. You need to simplify the XML representation of your message contract so that the namespace is only declared once. What should you do?（）

• A、Declare a wrapper namespace for the message contract by using the WrapperNamespace property of the MessageContract attribute
• B、Explicitly set the Namespace property of all the MessageBodyMember attrbutes to the same namespace.
• C、Declare all of the body members as properties of a DataContract class and use the class as the only body member of the message contract.
• D、Declare all of the body members as properties of a separate MessageContract class and use the class as the only body member of the message contract.