The correct answer is A. Trigarta.
Trigarta was a mahajanapada (great kingdom) in the eastern Punjab region of the Indian subcontinent during the 6th and 5th centuries BCE. It was located in the regions of Taxila, Western Kangra upto Hoshiarpur. The capital of Trigarta was Taxila.
The Audumbaras were a mahajanapada located in the region of present-day Ambala district in Haryana. The capital of the Audumbaras was Sakala.
The Kulutas were a mahajanapada located in the region of present-day Kullu district in Himachal Pradesh. The capital of the Kulutas was Ahichatra.
The Kulindas were a mahajanapada located in the region of present-day Kumaon region in Uttarakhand. The capital of the Kulindas was Kalinga.
Trigarta was a powerful kingdom and was often at war with the neighboring kingdom of Gandhara. The Trigartas were known for their military prowess and their cavalry was considered to be one of the best in the subcontinent.
The Trigartas were also known for their culture and learning. The city of Taxila was a major center of learning and attracted students from all over the subcontinent.
The Trigartas were eventually conquered by the Mauryan Empire in the 4th century BCE. However, their culture and legacy continued to influence the region for centuries to come.