The second urbanization started in the 6th century BC in the Indian subcontinent. Hence, Statement 3 is incorrect.
It is an era associated with early states, cities, the growing use of iron, the development of coinage, etc.
It also witnessed the growth of diverse systems of thought, including Buddhism and Jainism.
The centre of economic and political activity shifted from north-west to Eastern UP and Bihar that is the Ganga basin.
The territorial States become very large with the use of better tools and weapons and came to be known as Mahajanapadas.
The small kingdoms submitted to the stronger ruler or gradually got eliminated.
While most Mahajanapadas were ruled by kings, some, known as ganas or sanghas, were oligarchies where power was shared by a number of men, often collectively called rajas. Hence, Statement 1 is correct and Statement 2 is incorrect.
Both Mahavira and the Buddha belonged to such ganas.
In some instances, as in the case of the Vajji sangha, the rajas probably controlled resources such as land collectively.
Each Mahajanapada had a capital city, which was often fortified.
Maintaining these fortified cities as well as providing for incipient armies and bureaucracies required resources.