We must work hard
(a) because
(b) so that
to extricate our country from poverty.
(c) such that
(d) in order

I say D because “We must work hard in order to fix our bad habit” makes the most sense.

according to classical republican political theory, which democratic republics would function best?

a.   small republics, with people who had similar interests

b.   large republics, with people who had competing interests

c.   republics made up entirely of landowners

d.   republics made up entirely of servants

if you have to make a general question and respond to your thoughts, then this isn't really a question someone can you on. read the passage, form your question, and answer using your thoughts. no one else can understand how you interpreted this text if you don't tell us.