A. by organizing voter registration drives in immigrant neighborhoods
Explanation:
The political machines were a group of self-acclaimed bosses in the 19th and early 20th centuries who controlled the political affairs of the cities in the United States of America. Tammany Hall was one such person who wielded a lot of political influence in New York City. They canvassed for votes from the people in return for favors such as employment. These bosses became so powerful and politically strong.
There were many who did not like this form of monopoly and endeavored to overturn the way things were done. These reformers tried to achieve their aim through voter registration campaigns among the citizens with the goal of voting out the political machines.
The gravity of the Sun keeps the planets in their orbits. They stay in their orbits because there is no other force in the Solar System which can stop them.
