What Explains the Appreciation of the Japanese Yen Relative to the U.S.dollar

What explains the appreciation of the Japanese yen relative to the U.S.dollar from 1970 to the early 1990s?

A) Japanese productivity rose faster than U.S.productivity.
B) Japanese inflation rose faster than U.S.inflation.
C) U.S.consumers reduced their preferences for Japanese goods.
D) High tariffs and restrictive quotas in the United States caused the value of the dollar to decline.