You are upgrading a stand-alone Windows Presentation Foundation (WPF) application and
an XAML browser application (XBAP) to Microsoft .NET Framework 4. You plan to add
.NET 4 types and members to both applications. Both applications consume a common
utility assembly that modifies files on a local file system. The utility assembly requires full
trust. You need to ensure that both applications can use the common utility assembly
without any security-related exceptions. What should you do?

A.
Change the <supportedRuntime> element for the XBAP application to the .NET
Framework 3.5.

B.
Apply the AllowPartiallyTrustedCallersAttribute attribute to the utility assembly.

C.
Apply the AllowPartiallyTrustedCallersAttribute attribute to the XBAP application.

D.
Change the <supportedRuntime> element for the WPF application to the .NET
Framework 3.5.

Explanation: