Dalkhai is a popular folk dance of:

The correct answer is Odisha.

Explanation:
Dalkhai is one of the most popular folk dance forms of Odisha, originating particularly in the western parts of the state, such as Sambalpur, Balangir, Bargarh, and Sonepur districts.
It is traditionally performed by young girls of various tribes during festivals, most notably during Bhaijiuntia, Nuakhai, and Dussehra. The dance is accompanied by traditional musical instruments like the Dhol, Nishan, Tamki, Tasa, and Mahuri. The theme of the songs sung during the dance usually revolves around the love story of Radha and Lord Krishna, as well as descriptions of nature.