The Fifteenth Amendment had a significant loophole: it did not grant suffrage to all men, but only prohibited discrimination on the basis of race and former slave status. States could require voters to pass literacy tests or pay poll taxes - difficult tasks for the formerly enslaved, who had little education or money.
The best way to measure public opinion is through opinion polls - B
With opinion polls you get an idea what is the general idea about a certain topic from the public, as you usually get a high enough sample to deduce the relevant information.
To answer your second question I would say it is either B or C as being a sole proprietor usually makes you subjec to being a small business or you're forced to use factors of production less efficiently.
I have no clue man just go to page 331 and you will find the answer
The harsh living conditions in New York City slums