Final answer:
Politician George Plunkett belonged to a political machine. Therefore, the correct option is B. a political machine.
Step-by-step explanation:
Based on the description provided, politician George Plunkett belonged to a political machine. The given excerpt describes Plunkett as someone who understood that in politics, factors such as honesty, efficiency, and progressive vision do not matter. Instead, what matters to him is the chance for better job opportunities, prices for agricultural products like wheat, and improved business conditions.
This aligns with the characteristics of a political machine, which is an informal political group led by a powerful party boss that aims to gain and maintain power by offering various benefits to citizens in exchange for their votes.