Step 1: Identifying Assam's culture.
Bihu is the most important traditional dance form of Assam. It is performed during the Bihu festival, celebrating the Assamese New Year.
Step 2: Bihu dance details.
This dance is characterized by rapid movements and traditional folk music, representing the joyous celebrations during the Bihu festival.
Step 3: Conclusion.
Thus, the state dance of Assam is Bihu, so option (2) is correct.