You upgrade a Windows Forms application to Microsoft .NET Framework 4. The application was developed
by using a previous version of the .NET Framework. The application uses the Code 
Access Security (CAS) policy for file access. 
When the application is executed, you receive the following exception:  
"NotSupportedException: This method uses CAS policy, which has been obsoleted by the .NET Framework." 
You need to resolve the error. 
What should you do?（）

You use Microsoft .NET Framework 4 to create a Windows Forms application. 
You plan to use a Windows Presentation Foundation (WPF) control of the UserControl1 type hosted in an
ElementHost control named elementHost1. 
You write the following code segment. (Line numbers are included for reference only.)

You need to ensure that the application changes the background color of the hosted control when the background color of the form changes.  
Which code segment should you insert at line 05?（）