The correct answer is: a) Rivers.
Rivers are the most important source of fish for the people of Assam. They provide a livelihood for millions of people and are a vital part of the state’s economy. The main rivers in Assam are the Brahmaputra, the Barak, and the Manas.
Beels (wetlands) are also important for fishing, but they are not as important as rivers. Beels are areas of low-lying land that are flooded during the monsoon season. They provide a habitat for a variety of fish, including carp, catfish, and tilapia.
Reservoirs are artificial lakes that are created by damming rivers. They are not as important for fishing as rivers or beels, but they do provide a habitat for some fish species.
Ponds are small artificial lakes that are used for irrigation and aquaculture. They are not as important for fishing as rivers, beels, or reservoirs.
In conclusion, the majority of fishing in Assam is carried out in rivers. Rivers are the most important source of fish for the people of Assam and provide a livelihood for millions of people.