You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4.0 to create an application. The application contains the following XML document: <bib> <book title="TCP/IP Illusrated"…

You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4.0 to create an application. The application contains the following XML document:

<bib> <book title="TCP/IP Illusrated" year="1994"> <author>Author1</author> </book> <book title="Programming in UNIX" year="1992"> <author>Author1</author> <author>Author2</author> <author>Author3</author> </book> <book title="Data on the web" year="2000"> <author>Author4</author> <author>Author3</author> </book> </bib> You add the following code fragment. (Line numbers are included for reference only.) 01 public IEnumerable<XElement> GetBooks(string xml) 02 { 03 XDocument doc = XDocument.Parse(xml); 04 ... 05 } You need to return a list of book XML element that are authored by Author1. Which code segment should you insert at line 04?