The correct answer is Palamu.
Palamu was a princely state in India, located in the present-day state of Jharkhand. It was founded in the 14th century by the Chero dynasty. The capital of Palamu was the town of Daltonganj.
The Palamu Fort is a 16th-century fort located in the town of Daltonganj. It is one of the largest forts in India. The fort was built by the Chero kings to protect their kingdom from the Mughals.
The fort is a strategic hill fort. It is located on a hilltop and is surrounded by a moat. The fort has a number of towers and bastions. The fort is also home to a number of temples and palaces.
The Palamu Fort is a popular tourist destination. It is also a UNESCO World Heritage Site.
The other options are incorrect because they are not princely states that had a strategic hill fort as their major defensive structure.
Hutwa is a village in the Palamu district of Jharkhand, India. It is located on the banks of the Son River.
Rajnagar is a town in the Palamu district of Jharkhand, India. It is the headquarters of the Rajnagar block.
Sonbarsa is a village in the Palamu district of Jharkhand, India. It is located on the banks of the Son River.