The correct answer is: Sarhul.
Sarhul is a festival celebrated by the Munda and Oraon tribes of Jharkhand. It is considered as the first festival of the year and is celebrated to mark the beginning of the new agricultural year. The festival is also a thanksgiving to the gods for a good harvest.
Rohini is a Hindu festival celebrated in the month of Magha (January-February). It is dedicated to the goddess Rohini, who is the wife of the moon god Chandra. The festival is celebrated to mark the beginning of the spring season.
Hal Punhya is a Hindu festival celebrated in the month of Chaitra (March-April). It is dedicated to the god Vishnu. The festival is celebrated to mark the beginning of the harvesting season.
Tusu is a Hindu festival celebrated in the month of Paush (December-January). It is dedicated to the goddess Tusu, who is the goddess of harvest. The festival is celebrated to mark the beginning of the winter season.
Sarhul is a more important festival than the other three festivals mentioned in the question. It is celebrated by a larger number of people and is considered to be a more auspicious festival.