多项选择题 You use Microsoft .NET Framework 4 to create a Windows application. You plan to deploy the application by using Trusted Application Deployment. The application can only be installed by users who have elevated permissions. You need to ensure that users are not prompted for additional permissions when they install the application. Which two actions should you perform? （）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application displays a list of books. You write the following code fragment. (Line numbers are included for reference only.) You need to ensure that book titles that are out of stock appear in red. Which code fragment should you insert at line 12?（）

单项选择题 You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. The application contains a set of Button controls. You need to ensure that a button is highlighted when the mouse pointer is located over a button that contains no content. Which code fragment should you use?（）