A．To show the inability of trains to compete with planes with respect to speed and convenience.
B．To stress the influence of the automobile on America’’s standard of convenience.
C．To emphasize the function of travel agencies in market promotion.
D．To illustrate the important role of persuasive communication in changing consumer attitudes.

A．They make decisions by tossing coins.
B．They are not physically separated.
C．They think exactly the same way.
D．They share most of their vital organs.