The correct answer is: d) Mahseer.
Mahseer is a large freshwater fish found in Asia. It is a popular game fish and is also an important food fish in many parts of its range. Mahseer are known for their fighting spirit and are often considered to be one of the most challenging fish to catch.
There are many different species of mahseer, but the most common species found in Nagaland is the Tor khudree. Tor khudree is a medium-sized fish that can grow up to 1 meter in length. It is a silvery-green fish with a dark stripe along its back. Tor khudree is found in rivers and streams throughout Nagaland. It is a popular game fish and is also an important food fish.
The other options are incorrect because they are not common fish species found in Nagaland’s rivers. Rohu is a carp that is found in rivers and lakes throughout India. Catla is another carp that is found in rivers and lakes throughout India. Trout are freshwater fish that are found in cold, clear streams and rivers in the Northern Hemisphere.