The correct answer is D) consisting of many islands.
The feature of Japan that made it difficult to unify and govern is that Japan has many islands.
The Japanese archipelago consists of many islands, that originally, was a problem to unify Japan in one single and solid nation. It was a difficult territory to establish good communications and exchange or trade of products was not easy as well.
Of all the Japanese territory, only 430 islands are inhabited of the total of 6,852. The main islands are Kyushu, Honshu, Shikoku, and Hokkaido. Japan's capital city, Tokyo, is located in the Honshu island.
