The correct answer is (b), West Bengal.
The Gangasagar Mela is a Hindu pilgrimage that takes place every year on the Magha Purnima day in the month of January or February. It is held at the confluence of the Ganges, Brahmaputra, and Meghna rivers in the Sagar Island in West Bengal. The mela is one of the largest religious gatherings in the world, with over 10 million pilgrims attending each year.
The pilgrims come to Gangasagar to take a dip in the holy waters of the Ganges, which is believed to cleanse them of their sins. They also offer prayers to the Hindu deities and attend religious ceremonies. The mela is a time of celebration and festivity, and the pilgrims enjoy a variety of cultural performances and other activities.
The other options are incorrect. Gujarat is a state in western India. Andhra Pradesh is a state in southern India. Rajasthan is a state in northwestern India.