Which code segment should you use?

You are creating a Windows Workflow Foundation custom activity by using Microsoft .NET Framework 3.5.

The custom activity has the following features:

It implements the IEventActivity interface.
It implements the CreateWorkflowQueue method that configures and returns a WorkflowQueue object.

The Subscribe method of the custom activity receives the following parameters:

An ActivityExecutionContext parameter named parentContext An IActivityEventListener<QueueEventArgs> parameter named parentEventHandler

You need to use a WorkflowQueue object to implement the Subscribe method.

Which code segment should you use?

A.
WorkflowQueue queue = CreateWorkflowQueue(parentContext);queue.Enqueue(parentEventHandler);

B.
WorkflowQueue queue =
CreateWorkflowQueue(parentContext);queue.RegisterForQueueItemAvailable(parentEventHandler);

C.
WorkflowQueue queue =
CreateWorkflowQueue(parentContext);queue.UnregisterForQueueItemAvailable(parentEventHandler);

D.
WorkflowQueue queue =
CreateWorkflowQueue(parentContext);parentEventHandler.OnEvent(parentContext, queue.Dequeue() as QueueEventArgs);