The correct answer is: a) Hilly areas with steep slopes.
Hilly areas with steep slopes are most vulnerable to landslides because they have a higher potential for soil erosion and instability. The steep slopes can also make it difficult to evacuate people and property in the event of a landslide.
Coastal plains are less vulnerable to landslides because they are typically made up of softer materials that are less likely to erode. Densely forested regions are also less vulnerable to landslides because the trees help to hold the soil in place. River banks are more vulnerable to landslides because they are often undercut by the river, which can cause the soil to collapse.
Here are some additional details about each option:
- Hilly areas with steep slopes are most vulnerable to landslides because they have a higher potential for soil erosion and instability. The steep slopes can also make it difficult to evacuate people and property in the event of a landslide.
- Coastal plains are less vulnerable to landslides because they are typically made up of softer materials that are less likely to erode.
- Densely forested regions are also less vulnerable to landslides because the trees help to hold the soil in place.
- River banks are more vulnerable to landslides because they are often undercut by the river, which can cause the soil to collapse.