You are developing an application to update a user’s social status. You need to consume the service using Windows Communication Foundation (WCF). The client configuration is as follows.
<system.serviceModel>
<bindings>
<webHttpBinding>
<binding name=”SocialConfig”>
<security mode=”TransportCredentialOnly”>
<transport clientCredentialType=”Basic” ?realm=”Social API” />
</security>
</binding>
</webHttpBinding>
</bindings>
<client>
<endpoint address=”http://contoso.com” binding=”webHttpBinding” bindingConfiguration=”SocialConfig” contract=”ISocialStatus” name=”SocialClient” />
</client>
</system.serviceModel>
The service contract is defined as follows.
<ServiceContract()>
Public Interface ISocialStatus <OperationContract()> <WebInvoke(UriTemplate:=”/statuses/update.xml?status={text}”)> Sub UpdateStatus(ByVal text As String) End Interface
Which code segment should you use to update the social status?

A.
Using factory As WebChannelFactory(Of ISocialStatus) = New WebChannelFactory(Of ISocialStatus)(“SocialClient”) factory.Credentials.UserName.UserName = user.Name
factory.Credentials.UserName.Password = user.Password Dim socialChannel As ISocialStatus = factory.CreateChannel() socialChannel.UpdateStatus(newStatus) End Using

B.
Using factory As ChannelFactory(Of ISocialStatus) = New WebChannelFactory(Of ISocialStatus)(GetType(ISocialStatus)) factory.Credentials.UserName.UserName = user.Name factory.Credentials.UserName.Password = user.Password Dim socialChannel As ISocialStatus = factory.CreateChannel() socialChannel.UpdateStatus(newStatus) End Using

C.
Using factory As ChannelFactory(Of ISocialStatus) = New ChannelFactory(Of ISocialStatus)(“POST”) factory.Credentials.Windows.ClientCredential.UserName = user.Name factory.Credentials.Windows.ClientCredential.SecurePassword.SetAt( 0, user.Password) Dim socialChannel As ISocialStatus = factory.CreateChannel() socialChannel.UpdateStatus(newStatus) End Using

D.
Using factory As WebChannelFactory(Of ISocialStatus) = New WebChannelFactory(Of ISocialStatus)(GetType(ISocialClient))
factory.Credentials.Windows.ClientCredential.UserName = user.Name factory.Credentials.Windows.ClientCredential.SecurePassword.SetAt( 0, user.Password) Dim socialChannel As ISocialStatus = factory.CreateChannel() socialChannel.UpdateStatus(newStatus) End Using