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.
ITS A.VENN DIAGRAM.................................................
Answer:
Economic
Explanation:
It greatly effected people economically who went from poor to rich.