Question

companies hired pinkertons to report on and bust unions. negotiate with unions in the workplace. force scabs to cross picket lines. move employees to company towns.

Explanation:

The Pinkertons were often used by companies to gather information on unions and take actions to disrupt or break them up during labor - management conflicts in history. They were not typically hired for negotiating with unions, forcing scabs to cross picket lines, or moving employees to company towns as their main function.

Answer:

report on and bust unions.