"You must enable the /catalog.svc IItems operation to respond using the POX, JSON, or ATOM formats. You also must ensure that the same URL is used regardless of the result type. You must determine the response format by using the Accepts HTTP header. What should you do?
Implement the IChannellnitializer interface in the service class
Implement the System.Runtime.Serialization.IFormatterConverter interface in the service class.
Set the BodyStyle parameter of the WebGet attribute on the operation to WebMessageBodyStyle. WrappedResponse.
Set the retum type of the operation to System.ServiceModel.Channels.Message. Use the current WebOperationContext methods to return the data in the required format.