Which is the best way to measure public opinion?
a. the media
b. opinion polls
c. interest groups
d. elected officials
sole proprietorships produce only a small fraction of annual sales in the u. s. economy because sole proprietorships
a. are the most heavily taxed businesses.
b. mainly are small businesses.
c. use the factors of production less efficiently.
d. have less flexibility in decision making.

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. 

The views of many people.