You use Microsoft .NET Framework 4 to create a Windows Forms application.
You write the following code segment. (Line numbers are included for reference only.)
01sealed class FormSettings :

You need to ensure that the first time each user opens the application, a text field displays the following message: "Please enter your setting."
Which code segment should you insert at line 03?（）

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?（）