According to the author, the deeper problems of aviation industry ______.

A．Governmental restrictions are still imposed on aviation industry in many areas.
B．Governments help establish rules for aviation industry only in America and Europe.
C．Some countries hope to help their national carriers keep up their national prestige.
D．Many countries discourage merger plans between foreign and domestic carriers.

A．free competition may help solve the problems confronting aviation industry
B．problems in America are more of a political nature than that in Europe
C．car industry should exert a more powerful influence on aviation industry
D．there is still a long way to go before the problems can be solved