The far-northern island of Japan is :

Kyushu
Shikoku
Hokkaido (Hokaido)
Honshu

The correct answer is (c), Hokkaido. Hokkaido is the northernmost and second largest island of Japan. It is separated from Honshu, the main island of Japan, by the Tsugaru Strait. Hokkaido is home to Mount Asahi, the highest mountain in Japan outside of the Japanese Alps. The capital of Hokkaido is Sapporo, which is known for its annual Sapporo Snow Festival.

(a) Kyushu is the southernmost of the four main islands of Japan. It is home to the cities of Fukuoka, Nagasaki, and Kumamoto.

(b) Shikoku is the smallest of the four main islands of Japan. It is home to the cities of Kochi, Matsuyama, and Takamatsu.

(d) Honshu is the main island of Japan. It is home to the cities of Tokyo, Osaka, and Kyoto.