If the U.S. dollar appreciates relative to the yen, it means that one U.S. dollar is worth more yen than before. As a result, holders of U.S. dollars will find that Japanese automobiles priced in yen are relatively less expensive because they can now buy more yen with each dollar.
Therefore, the correct response is:
Since one U.S. dollar is worth more yen, Japanese automobiles are relatively less expensive to holders of U.S. dollars.