Question

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

Explanation:

The Pinkertons were private detective agencies often hired by companies during labor - management conflicts. Their main role was to report on union activities and take actions to break up unions, such as using force and intimidation. They were not primarily involved in moving employees to company towns, negotiating with unions in a positive sense, or just forcing scabs to cross picket lines. Their focus was on undermining union power.

Answer:

report on and bust unions