**Hill: A Land Surface Higher than the Local Area**

A land surface that is higher than the surrounding local area is referred to as a hill. It is a geographical feature that is characterized by its elevation and slope. Hills can be found in various landscapes across the world, ranging from gentle rolling hills to steep and rugged terrain. Here's a detailed explanation of why the correct answer is option 'D' - Hill:

**Definition of a Hill:**
A hill is defined as a raised area of land with sloping sides and a rounded or flattened summit. It is generally smaller in size and lower in elevation compared to mountains. Hills are often created through various geological processes such as tectonic activity, erosion, and volcanic activity.

**Characteristics of a Hill:**
1. Elevation: A hill is a landform that is higher than the local area, but it is not as high as a mountain. The exact height of a hill can vary significantly depending on the region and the context in which it is being referred to.

2. Sloping sides: Unlike a plateau or a mountain, hills have sloping sides that gradually ascend from the surrounding area. The slope of a hill can vary in steepness, ranging from gentle slopes to more pronounced inclines.

3. Summit: At the top of a hill, there is a rounded or flattened summit. Although the summit of a hill is not as sharp or jagged as that of a mountain, it still offers a vantage point and may provide scenic views of the surrounding landscape.

4. Size: Hills are generally smaller in size compared to mountains. While there is no specific size criterion to differentiate between a hill and a mountain, hills are typically less extensive in terms of their area.

**Difference between a Hill and other Landforms:**
1. Plateau: Unlike a plateau, which is a flat elevated land surface, a hill has sloping sides and a more pronounced elevation compared to the surrounding area.

2. Mountain: Mountains are much larger and higher in elevation compared to hills. They often have rugged and steep slopes, and their summits are typically more jagged and pointed.

3. Plain: A plain, also known as a lowland or a flatland, is the opposite of a hill. It is a flat or gently undulating land surface with no significant elevation changes. Plains are characterized by their low relief and lack of steep slopes.

In conclusion, a land surface that is higher than the local area and has sloping sides and a rounded or flattened summit is referred to as a hill. While it is smaller and lower in elevation compared to mountains, it offers an elevated vantage point and adds diversity to the landscape.