Final answer:
Kauai in Hawaii, with its dormant volcanoes, is the least in need of advanced volcano monitoring systems compared to the actively threatening volcanoes Mount Rainier, Kilauea, and Mount Fuji.
Step-by-step explanation:
Among the volcanoes listed, Kauai in Hawaii is the least in need of a state-of-the-art volcano monitoring system. Kauai is home to dormant volcanoes that are not currently showing signs of activity. In contrast, Mount Rainier is an active stratovolcano with a significant risk of future eruptions, Kilauea is among the world’s most active volcanoes, and Mount Fuji in Japan is an active stratovolcano and also a significant risk due to its proximity to populated areas. Given that Kauai's volcanic threat is minimal compared to the others, it would be deemed the least in priority for state-of-the-art monitoring.