KBC 2023| Mount Fuji is the highest mountain of which island nation? KBC 2023, Check the answer to the question- Mount Fuji is the highest mountain of which island nation? By Himani Budakoti - September 18, 2023 KBC 2023, Amitabh Bachchan. (Representative Image) KBC 2023, The options of the question – Mount Fuji is the highest mountain of which island nation? A. Japan B. China C. Nepal D. Bhutan The answer is A. Japan.