Final answer:
The 12 Girls Band has seen its greatest positive reception in Japan, where they have become very popular due to their modern take on traditional Chinese music.
Step-by-step explanation:
The 12 Girls Band originates from the People's Republic of China (PRC) and has achieved international success. However, the country where they have attained their greatest positive reception is Japan. The band, which plays traditional Chinese instruments in a contemporary style, has had its music warmly received in Japan, leading to high popularity and sales. This contrasts with the other options provided (USA, France, and the PRC itself), where the band is known but has not reached the level of success seen in Japan.