The correct answer is option 'A', Someshwar Hilly Range.

The North-Western parts of Bihar State are characterized by various landforms. One of these landforms is the Someshwar Hilly Range. Let's explore this landform in detail.

Heading 1: Someshwar Hilly Range

The Someshwar Hilly Range is located in the northwestern part of Bihar State. It is a prominent landform that stretches across several districts, including Rohtas, Bhojpur, and Kaimur. This hilly range is an extension of the Vindhya Range, which runs through central India.

Key points:
- The Someshwar Hilly Range is known for its rugged terrain and rocky hills.
- It is a part of the Eastern Ghats, which are a range of mountains and hills that span across several states in eastern India.
- The highest peak in the Someshwar Hilly Range is Mount Kaimur, also known as Mundeshwari Peak, which reaches an elevation of around 880 meters.
- The hilly range is adorned with dense forests, making it a haven for various flora and fauna species.
- The forests also act as a watershed, providing water to several rivers and streams that originate in the region, such as the Sone River.
- The Someshwar Wildlife Sanctuary is located in this hilly range, which is home to several endangered species like the Indian wolf, sloth bear, and leopard.

Conclusion:
The Someshwar Hilly Range is a significant landform in the northwestern parts of Bihar State. It is characterized by its rugged terrain, rocky hills, and dense forests. The hilly range plays a crucial role in the region's ecology, acting as a watershed and providing habitat to various wildlife species.