Based on the political cartoon, which conclusion can be made about Boss Tweed and the Democratic Party political machine known as Tammany Hall?

Select one:
a. The substantial power held by Boss Tweed and Tammany Hall was achieved through political corruption.
b. Business monopolies controlled the voting rights of citizens through Boss Tweed.
c. The political machine became stronger as Boss Tweed built more factories.
d. The greediness of Boss Tweed led to his downfall and the subsequent rise of Tammany Hall.