You create a Windows application by using the .NET Framework 3.5. The application is used for data entry purposes. The application has the following features:

* Data is read from a shared Microsoft SQL Server 2008 database instance.
* Data entered and saved by the users is temporarily stored in a local SQL Server 2008 Compact edition database instance.
* When the users log off from the application, new records from the local database instance are synchronized to the shared database.
* You discover that the performance of the application is affected when multiple users log off from the application at the same time.

You need to design a performance improvement strategy for the application by using minimum amount of cost, time, and development effort. What should you do?

A.
Upgrade the local database to Microsoft SQL Server 2008 Express edition.

B.
Modify the application to synchronize data into the shared database as soon as the users save their work.

C.
Write a Web service that synchronizes data to the shared database. Call the service when the users log off from the application.

D.
Store the data entered by the users temporarily in an XML file. Merge the new records from the local XML file to the shared database when the users log off from the application.