The correct answer is: b) Flood.
A flood is an overflow of water that submerges land that is usually dry. Floods can be caused by heavy rains, melting snow, or dam failures. They can cause extensive damage to property and infrastructure, and can also lead to loss of life.
In Assam, floods are a major natural hazard. The state is located in the Brahmaputra River basin, which is one of the most flood-prone areas in the world. The Brahmaputra River is a major source of water for Assam, but it also carries a large amount of sediment. When the river floods, this sediment can deposit on land, causing soil loss and changes in river courses.
Floods can also lead to waterlogging. Waterlogging occurs when water accumulates in the soil to the point where it becomes saturated. This can damage crops and other vegetation, and can also make it difficult for people to move around.
In conclusion, the correct answer to the question “Which disaster leads to soil loss, waterlogging, and changes in river courses in Assam?” is b) Flood.