While Magadha was a powerful Mahajanapada, Vajji, with its capital at Vaishali (Bihar), was under a different form of government known as:

Gana or Sangha

The correct answer is Option 2- Gana or Sangha

The form of government in Vajji, with its capital at Vaishali (Bihar), was known as Gana or Sangha. It was a republican form of government, in which the people were ruled by a council of representatives from different clans and families. The council was known as the Gana Parishad or Sangha Sabha.

The other options are incorrect:

• Samajwad is the Hindi word for socialism.
• Loktantra is the Hindi word for democracy.
• Panchayati is a form of rural local government in India.

The Gana or Sangha form of government was a unique feature of Vajji, and it helped the Mahajanapada to become one of the most powerful in India. Vajji was able to resist the expansion of Magadha for many years, and it was only after a long and bloody war that Magadha was finally able to conquer Vajji in the 5th century BCE.