In some cases, the parsing behavior differs from the parsing behavior in Windows Presentation Foundation (WPF), which also has a particular implementation
The only supported xml: construct in Silverlight is xml:lang
Silverlight's XAML parser has limitations compared to WPF. Option B is correct because Silverlight does NOT support all XAML constructs mentioned - it has a more limited XAML namespace support than WPF. Silverlight supports x:Array, x:Class, x:Name, x:Key, x:Null, and x:Type, but NOT x:Code or x:Subclass.