Which base class should you use?

You are creating a workflow by using Microsoft .NET Framework 3.5. You use Windows Workflow Foundation to create the workflow.

You plan to create a custom activity for the workflow.

You need to ensure that the custom activity performs the following tasks:

Executes child activities to invoke a Web service.
Processes the Web service results.

You are creating a workflow by using Microsoft .NET Framework 3.5. You use Windows Workflow Foundation to create the workflow.

You plan to create a custom activity for the workflow.

You need to ensure that the custom activity performs the following tasks:

Executes child activities to invoke a Web service.
Processes the Web service results.

Which base class should you use?

A.
System.Workflow.Activities.CodeActivity

B.
System.Workflow.ComponentModel.Activity

C.
System.Workflow.Activities.SequenceActivity

D.
System.Workflow.Activities.InvokeWebServiceActivity