Which of the Following Was an Important Factor in Boosting

Which of the following was an important factor in boosting sales of Japanese cars during the 1970s?

A) the United States' comparative advantage in auto production
B) a shortage of U.S. cars at dealerships
C) the higher prices of Japanese cars compared to U.S. autos
D) the U.S. manufacturers' slow response to pressures to produce smaller cars
E) Japanese agreements to voluntary restrictions rather than quotas on their auto exports to the United States