XML LINQ C#

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XDocument xDocument = new XDocument(
          new XElement("Books",
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XElement("FirstName", "A"),
              new XElement("LastName", "B")),
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XElement("FirstName", "C"),
              new XElement("LastName", "D"))));
        Console.WriteLine("Here is the original XML document:");
        Console.WriteLine("{0}{1}{1}", xDocument, System.Environment.NewLine);
    }
}