One of the main problems with the indian reservation system was that government agents

One of the main problems with the Indian reservation system was that government agents often refused to adhere to the borders that had been agreed upon in Congress--instead often kicking the Natives off of their allotted territory. 

the correct answer is d: "party organizers, volunteers, voters, and elected officials."

party organizers: individuals responsible for designing strategies in order to better execute the political campaign. this includes the candidate's public relations. volunteers: individuals responsible for raising awareness regarding the candidates running for office.voters: individuals who are convinced by volunteers that a particular candidate is the best option.elected officials: winning candidate and his elected team are a product of a successful political campaign.

I'll go with that