The correct answer is (c). Nagaland is a mountainous state with a high altitude. The rivers in Nagaland are mostly fast-flowing and have steep gradients. This makes them difficult to navigate, especially during the monsoon season when the water levels are high. The state also has a well-developed road network, which makes road transport a more viable option.
(a) Strong river currents: The river currents in Nagaland are strong due to the high altitude and steep gradients of the rivers. This makes them difficult to navigate, especially during the monsoon season when the water levels are high.
(b) Well-developed road network: Nagaland has a well-developed road network. This makes road transport a more viable option than water transport.
(d) Seasonal variations in water levels: The water levels in the rivers of Nagaland vary significantly throughout the year. This is due to the monsoon season, which brings heavy rains to the state. During the monsoon season, the water levels in the rivers are high and the rivers are difficult to navigate. During the dry season, the water levels in the rivers are low and the rivers are more easily navigable.