Loading xml, linq with namespace using c#

I am following a tutorial and it works fine when i load a basic xml file.

xml

<?xml version="1.0" encoding="utf-8" ?>
<Students>
  <Student ID="1">
    <Name>Test1</Name>
  </Student>
  <Student ID="2">
    <Name>Test2</Name>
  </Student>
  <Student ID="3">
    <Name>Test3 </Name>
  </Student>
</Students>

---

C#

XDocument testXML = XDocument.Load(@"C:\Users\b\Desktop\SITE\xml.xml");
var students = from student in testXML.Descendants("Student")
               select new
               {
                   ID = student.Attribute("ID").Value
               };

foreach (var student in students)
{
    xmlTitle.Text += "</br>" + student.ID + " </br>";

}

output:

Now, I want to add this tag before the

<Students>

---

<outputTree xmlns="http://ift.tt/1sL7eZL" xmlns:xsi="http://ift.tt/ra1lAU" xsi:schemaLocation="http://ift.tt/1sL7eZL http://ift.tt/1sL7eZN">

I tried for ages but i cant get it working. when i add

XNamespace ns = "http://ift.tt/1sL7eZL";