An economic principle that explains why people pursue different occupations is

Suppose Julianna reads that Algeria's total spending on goods and services was $370 B in 2013. She also knows that ____

a. Algeria's net profits were $370 B b. Algeria's export sales were $370 B c. Algeria's real GDP was $370 B d. Algeria's value of consumer goods produced was $370 B e. all

Which of the following is an example of natural monopoly?

A) cellular phone companies in a large city B) local water utility companies C) major league sports franchises in the largest cities D) All of the above are natural monopolies.