Which of the following individuals was a boss of a political machine?
a). john sloan
b). george washington plunkitt
c). thomas nast
d). william m. tweed

The correct answer is option d). "William M. Tweed".

Explanation:

William Magear Tweed, was widely known as "Boss", for his role as leader of Tammany Hall, the Democratic Party political machine that participated actively during the 19th century, mainly in the New York City and State. The power and political influence of William M. Tweed were at his peak when he was director of multiple banks and business in New York City, making him the  third-largest landowner in the City.

i believe 5 is correct answer

it further strained relations between the north and the south and convinced