The correct answer is: A. Expansion of the Shivalik in the North-Eastern part of Haryana.
The Shivalik hills are a mountain range in the foothills of the Himalayas. They are located in the North-Eastern part of Haryana. The Piedmont soils are a type of soil that is found in the foothills of mountains. They are formed from the weathering of the rocks that make up the mountains. The Shivalik hills are made up of sedimentary rocks, which are rocks that are formed from the accumulation of sediment. The Piedmont soils in Haryana are therefore formed from the weathering of these sedimentary rocks.
The Aravalli hills are a mountain range that is located in the South of Haryana. They are not as old as the Shivalik hills and are not as high. The Aravalli hills are made up of igneous rocks, which are rocks that are formed from the cooling of magma. The Piedmont soils in Haryana are not formed from the weathering of these igneous rocks.
Therefore, the main reason for the occurrence of Shivalik and Piedmont soils in Haryana is the expansion of the Shivalik in the North-Eastern part of Haryana.