which doesnt belong and why?
1. terence powderly . wobblies . knights of labor . social reformers
2. skilled workers . samuel gompers . miners . american federation of labor
3. rutherford b. hayes . railroad strike . pittsburgh . andrew carnegie
4. pinkertons . haymarket . homestead strike . henry frick
5. american railraod union . eugene v. debs . pullman strike . alexander berkman