Explain the optimal strategy that a price discriminating firm would use when pricing in markets with different elasticities

Say that after graduation you live in Manhattan and you walk to work. Then, you got a raise and you take a taxi most days. As a result, GDP would most likely ___.

A. fall B. be unchanged C. rise

The phrase in the text, 'human beings are self-interested, not selfish' means that:

a. people are never selfish. b. people never act in a spiteful or belligerent manner. c. people never act in a fit of rage. d. people contribute to charities and they help others. e. people care only about themselves and their families.