The correct answers are:
- strikes
- collective bargaining (name given to negotiations between employers and groups of employees related to their working conditions)
- support of labor legislation
Blacklisting was in turn, a measure adopted in order to discourage workers to get involved with trade unions. Punitive blacklists were created to register employees who participated with trade unions. Explicit blacklisting has been outlawed in the US, although it is a practice that might continue occurring tacictly.