The capital of the mighty Vijayanagara Empire, now a UNESCO World Heritage Site:

Halebidu
Pattadakal
Hampi
Badami

The correct answer is C) Hampi.

Hampi is a UNESCO World Heritage Site in the Indian state of Karnataka. It was the capital of the Vijayanagara Empire from the 14th to the 16th centuries. The city is located on the banks of the Tungabhadra River and is known for its ruins of temples, palaces, and other monuments.

Halebidu is a town in the Hassan district of Karnataka, India. It is known for its Hoysala temples, which were built in the 12th and 13th centuries. The temples are made of sandstone and are decorated with intricate carvings.

Pattadakal is a town in the Bagalkot district of Karnataka, India. It is known for its group of Hindu and Jain temples, which were built in the 7th and 8th centuries. The temples are made of sandstone and are decorated with intricate carvings.

Badami is a town in the Bagalkot district of Karnataka, India. It is known for its group of Hindu and Jain temples, which were built in the 6th and 7th centuries. The temples are made of sandstone and are decorated with intricate carvings.

Hampi is the correct answer because it was the capital of the Vijayanagara Empire. The other options are all important historical sites, but they were not the capital of the Vijayanagara Empire.