Which of the following is one of the three largest prefectures in Japan?

Fukushima is recognized as one of the three largest prefectures in Japan, mainly due to its size and geographical area. It is located in the Tōhoku region on the northeastern part of Honshu, Japan's main island, and has a diverse landscape that includes mountains, plains, and a coastline along the Pacific Ocean. This combination of size and geography contributes to its classification as one of the larger prefectures.

The other mentioned areas, while significant in their own right, do not match the size criteria of the largest prefectures. Osaka, known for its economic significance and urban environment, is much smaller in terms of land area. Okinawa, although famous for its culture and tourism, is a group of islands and is also smaller in land area compared to Fukushima. Aichi is well-known for its industrial contributions and the city of Nagoya, but it does not surpass Fuji's size. Thus, the recognition of Fukushima in this context is well-supported by its physical dimensions within Japan.