how to return xml fron webmethod in webservice

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XML

how can i return xml from webservice .
i am doing this plz any one help

[webmethod]
public string gertdata()
{
   xdocument xd=xdocument.load("path");
   var query from  p in xd.descendants("item")
   select new 
   {
     name=p.element("title").value;
   };
   return query.tosring();
}

how to modify get data method so that i can return xml.
in clieny call i want to do like this

ds.writexml("path",xmlwritemode.writeschema);

i am trying this and not able to get that , i know i am returning string ,how to change getdata method.