问题：

[单选]

You are developing a Windows Communication Foundation (WCF) service that is hosted by a Windows Forms Application.The ServiceHost instance is created in the Form Constructor.You need to ensure that the service is not blocked while the UI thread is busy.
What should you do?（）

A . Decorate the service implementation class with the following line of code [ServiceBehavior(UseSyncronizationContext = false)]
B . Decorate the service implementation class with the following line of code [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple)]
C . Call the Invoke method of the form and supply a delegate.
D . Call the BeginInvoke method of the form and supply a delegate.