The correct answer is D) They created a cycle of favors for voters.
Political machines are difficult to break up because they created a cycle of favors for voters.
Political Machine is a party organization which has a strong leader or a solid group of leaders. They command a good number of votes to maintain control of a location, that could be a state, county or a city. Political Machines provide help and favors to voters in order to maintain their control. They are called “machines” for their system of efficient operation.