नासिक प्रशस्ति और नानाघाट अभिलेखों के साक्ष्यों के अनुसार, किस प्रमुख सातवाहन शासक ने दो अश्वमेध यज्ञ और एक राजसूय यज्ञ किया था?

In Ancient Indian Statecraft, Kautilya's 'Rajamandala' theory primarily deals with:

The First Buddhist Council was held at ______.

Which ancient Indian text contains references indicating that population counts or census-like records were maintained in ancient India?