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.
You must me 17 years of age to serve in the military
Commercial areas in a city are areas, districts, or neighborhoods primarily composed of commercial buildings, such as a strip malls, office parks, downtown, central business district, financial district, "Main Street", or shopping centers. Commercial activity within cities includes the buying and selling of goods and services in retail businesses, wholesale buying and selling, financial establishments, and a wide variety of uses that are broadly classified as "business." While commercial activities typically take up a relatively small amount of land, they are extremely important to a community's economy. They provide employment, facilitate the circulation of money, and often serve many other roles important to the community, such as public gathering and cultural events.