We can serialize and deserialize complex classes to xml and vice-versa. For example we have a xml:

<?xml version="1.0" encoding="utf-8" ?>
<Settings>
<UIObject>
<Question>ABC</Question>
<Question>XYZ</Question>
<Question>PQR</Question>
</UIObject>
<ApplicationRestart>
<Question>Resume</Question>
<Question>Restart</Question>
</ApplicationRestart>
<QuestionNumbering>
<Question>A</Question>
<Question>I</Question>
<Question>1</Question>
</QuestionNumbering>
<AnswerNumbering>
<Question>A</Question>
<Question>I</Question>
<Question>1</Question>
</AnswerNumbering>
<Seperator>
<Question>,</Question>
<Question>.</Question>
</Seperator>
</Settings>

Then we need to deserialize it. Here we create a class, say Settings to create root note of the xml document.
All the other nested sub-nodes are created as a list here. Therefore the complete class will be as:

public class Settings
{
  [XmlArray("UIObject")]
  [XmlArrayItem(ElementName = "Question")]
  public List<string> UIObject { get; set; }
  
  [XmlArray("ApplicationRestart")]
  [XmlArrayItem(ElementName = "Question")]
  public List<string> ApplicationRestart { get; set; }
  
  [XmlArray("QuestionNumbering")]
  [XmlArrayItem(ElementName = "Question")]
  public List<string> QuestionNumbering { get; set; }
  
  [XmlArray("AnswerNumbering")]
  [XmlArrayItem(ElementName = "Question")]
  public List<string> AnswerNumbering { get; set; }
  
  [XmlArray("Seperator")]
  [XmlArrayItem(ElementName = "Question")]
  public List<string> Seperator { get; set; } 
}


This class/model will use as base class to perform serialization/deserialization. Here is a example to complete these operations:
  XMLUtility objXml = new XMLUtility();
  Settings objSetting = new Settings();

  List<string> Ques = new List<string>();
  Ques.Add("RADIONBUTTON");
  Ques.Add("CHECKBOX");
  Ques.Add("DROPDOWNLIST");
  objSetting.UIObject = Ques;
  
  Ques = new List<string>();
  Ques.Add("Resume");
  Ques.Add("Restart");
  objSetting.ApplicationRestart = Ques;
  
  Ques = new List<string>();
  Ques.Add("A");
  Ques.Add("I");
  Ques.Add("1");
  objSetting.QuestionNumbering = Ques;
  
  Ques = new List<string>();
  Ques.Add("A");
  Ques.Add("I");
  Ques.Add("1");
  objSetting.AnswerNumbering = Ques;
  
  Ques = new List<string>();
  Ques.Add(",");
  Ques.Add(".");
  objSetting.Seperator = Ques;
  
  /// convert object to xml string
  string xml = objXml.CreateXML(objSetting);
  Response.Write(xml);
  
  /// convert xml string to object.
  Settings obj2 = (Settings)objXml.CreateObject(xml, new Settings());

In this way we can serialize and deserialize even more complex classes.