You create a Windows application by using the .NET Framework 3.5. You review the design for a Windows application that has the following features:

* The data layer sends and receives data updates by using Microsoft Messaging Queue (MSMQ) 4.0.
* Data is stored in a Microsoft SQL Server 2008 server database instance.
* Data from a DataSet object is displayed in a DataGrid control.
* The application is deployed to portable computers that can access the corporate network only when plugged on to it.
* The data must be most securely stored when the computer is in offline mode.

You need to ensure that the portable computers can update data even when offline. What should you do?

A.
Change the data layer to use a local XML file instead of MSMQ.

B.
Change the data layer to use a local data cache along with Microsoft Sync Services instead of MSMQ.

C.
Create an ASP.NET Web service to receive data updates from the portable computers.

D.
Create a Windows Communication Foundation (WCF) service to send and receive data updates from the portable computers.