The correct answer is: b) Beels (wetlands).
Beels are depressions in the ground that are filled with water. They are formed when rivers change course or when the land subsides. Beels are important ecosystems that provide habitat for a variety of plants and animals. They also play a role in flood control and water purification.
Canyons are deep, narrow valleys that are carved out by rivers. They are formed when the river erodes the land over time. Canyons are often very beautiful and popular tourist destinations.
Sand dunes are hills of sand that are formed by the wind. They are found in deserts and other areas with a lot of wind. Sand dunes can be very large and can move over time.
Lava fields are areas of land that are covered in lava. Lava is molten rock that flows from volcanoes. Lava fields can be very dangerous because they are hot and can cause burns.
I hope this helps!