As noted in the text, the major Japanese auto manufacturers agreed to "voluntary" import ...

As noted in the text, the major Japanese auto manufacturers agreed to "voluntary" import restrictions that reduced the number of cars they could ship to the U.S. market in the 1980s.  One of the key outcomes from this policy is that the Japanese manufacturers were able to:
A) focus on more profitable auto markets in other countries.
B) raise their prices of autos in the U.S. market and capture higher profit margins on the imported cars.
C) cut their costs by more than the import tariff, so profit per auto increased.
D) all of the above