Type t = Type.GetType("clsCountrySelectInsertUpdate_TEST");
dynamic dd = Activator.CreateInstance(t, null);
dd.intMode = 203;
ThreadPool.QueueUserWorkItem(new WaitCallback(dd.CountrySelectInsertUpdate));

ThreadPool.QueueUserWorkItem(new WaitCallback(dd.CountrySelectInsertUpdate()),null);

ThreadPool.QueueUserWorkItem(new WaitCallback(state => dd.CountrySelectInsertUpdate()), null);

Task.Factory.StartNew( () => dd.CountrySelectInsertUpdate());