Which assembly or namespace should we use to include a Json object,Json array or any any Json related operations.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.IO;
using System.Text;
//using Oracle.DataAccess.Client;
using Timex.EmployeeLifeCycle;
using System.Data;
using System.Data.OracleClient;
using System.Configuration;
using Timex.Shared;
using Timex.Project;

public partial class PM_Roots_RootChild : System.Web.UI.Page
{
    clsFunction fun = new clsFunction();
    App_Common objMessage = new App_Common();
    Common objBl = new Common();
    RootChild rs = new RootChild();
    string emp_mid;

     
    protected void Page_Load(object sender, EventArgs e)
    
    {
        emp_mid= txtEmpmid.Text;
        
        GenerateFlowChart();

        //UCpeople.txtSearchChange += new EventHandler(UCpeople_txtSearchChange);

        if (!Page.IsPostBack)
        {
            
        }
        //txtEmpmid.Attributes.Add("onblur", "javascript:init('" + txtEmpmid.ClientID + "', '" + txtEmpname.ClientID + "')");
        //txtEmpmid.Attributes.Add("onblur", "javascript:initTest('" + txtEmpmid.ClientID + "','" + txtEmpname.ClientID + "')");
        txtEmpmid.Attributes.Add("onblur", "javascript:initTest('" + txtEmpmid.ClientID + "','" + hdnJsonData.ClientID + "')");
        btnShowGraph.Attributes.Add("onClick", "javascript:ReloadFrame('" + frmCtrl.ClientID + "','" + hdnJsonData.ClientID + "')");

        //frmCtrl.s
       
    }

    //void UCpeople_txtSearchChange(object sender, EventArgs e)
    //{
    //    if (!UCpeople.Text.Equals(""))
    //    {
    //        DataSet ds = new DataSet();
    //        ds = rs.Select_emp(emp_mid);
    //        UCpeople.Text = UCpeople.Value;
    //        if (ds.Tables.Count != 0)
    //        {
    //            txtEmpmid.Text = ds.Tables[0].Rows[0]["EMP_NAME"].ToString().Replace(" ", "");
    //        }
    //    }
    //}


    
    private void GenerateFlowChart()
    {
        try
        {
            Timex.Project.RootChild rc = new Timex.Project.RootChild();
            rc.GenarateFlow(UCpeople.Value, ddpLevel.SelectedValue);
            DataTable dt = new DataTable();
            dt = fun.GetDataTable("SELECT * FROM TEMP_FLOW_REPORT ORDER BY FLOW_LEVEL, emp_mid");
            StringBuilder sb = new StringBuilder();
            sb.Append (Write_Header()).AppendLine();
            sb.Append("function init(){").AppendLine();
            sb.Append("    //init data").AppendLine();
            sb.Append("    var json = {").AppendLine();
            //sb.Append("        id: " + (char)34 + UCpeople.Code + (char)34 + ",").AppendLine();
            sb.Append("        id: " + (char)34 + "EM000751" + (char)34 + ",").AppendLine();
            sb.Append("        name: " + (char)34 + UCpeople.Text + (char)34 + ",").AppendLine();
            sb.Append("        data: {},").AppendLine();
            sb.Append(Write_Parent(dt, UCpeople.Value)).AppendLine();
            sb.Append("};").AppendLine();
            sb.Append(Write_Footer()).AppendLine();
            sb.Append("}").AppendLine();
            //System.IO.File.WriteAllText(@"D:\OSOURCE-ONEX\Application Source Code\trunk\Code\PM\Roots\js\example_new.js", sb.ToString());

        }
        catch (Exception ex)
        {
            throw ex; 
        }
    }
}