The correct answer is C) Korea introduced Japan to the horse and to terrace farming, which allowed Japan to grow crops on mountainous terrain.
One way Japan's closest neighbor, Korea, has affected Japan's development is that Korea introduced Japan to the horse and to terrace farming, which allowed Japan to grow crops on mountainous terrain.
Japan has a small territory. Indeed, it's a group of islands. The geography of Japan is a mountainous territory difficult for farming. Koreans were the ones who introduced terrace farming, helping the Japanese to grow crops on the mountains. This and the horses brought by Koreans represented great opportunities for advancement for the rising Sun nation. Today South Korea and Japan have good relationships and cooperation agreements. The problem is North Korea, that has a tense relationship with Japan.