To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) The Visual Studio 2010 Report Viewer controls do not support the SQL Server 2005 version of Reporting Services report server - This option is correct. Visual Studio 2010 Report Viewer controls do not support the SQL Server 2005 version of Reporting Services report server. This means that if you are using the SQL Server 2005 version of Reporting Services, you will not be able to use the Report Viewer controls in Visual Studio 2010.
Option B) Microsoft Word is added as an export format for report generation - This option is incorrect. In Visual Studio 2010, Microsoft Word is added as an export format for report generation. This allows users to export reports in Word format.
Option C) Visual Studio 2010 provides a new Report Wizard that simplifies data definition and report design by guiding you step-by-step through a series of tasks that lead to a finished report - This option is incorrect. Visual Studio 2010 does provide a new Report Wizard that simplifies data definition and report design. The Report Wizard guides you through a series of tasks to create a finished report.
Option D) You cannot process your existing RDL 2005 reports in the Visual Studio 2010 Report Viewer controls - This option is correct. You cannot process your existing RDL 2005 reports in the Visual Studio 2010 Report Viewer controls. This means that if you have reports created in the RDL 2005 format, you will not be able to use them with the Report Viewer controls in Visual Studio 2010.
Option E) The new Tablix and gauge data regions and enhanced chart data regions in Report Designer are the enhancements in VS 2010 for Report creation - This option is incorrect. The new Tablix and gauge data regions and enhanced chart data regions are indeed enhancements in Visual Studio 2010 for report creation. These enhancements provide more flexibility and options for designing and displaying data in reports.
The correct answer is Option D. This option is correct because you cannot process your existing RDL 2005 reports in the Visual Studio 2010 Report Viewer controls.