Which approach should you recommend?

You are designing a SharePoint 2010 application. A Windows Communication Foundation (WCF) service
provides a connection to company information.
You need to design a list that gets its data from the WCF service.
Which approach should you recommend?

A.
Create an external content type and set the External Data Source Type to WCF Service.
Create a list that uses this external content type as its source.

B.
Create an external content type and set the External Data Source Type to .NET Type.
Create a list that uses this external content type as its source.

C.
Create an external list and set the External Content Type property to the URL of the WCF service.

D.
Create an external list and set the External Content Type property to the Web Service Definition Language (WSDL) file of the WCF service.