इतिहासकार आर.पी. चंदा द्वारा प्रस्तुत सजातीय सिद्धांत (ethnographic theory) के अनुसार, बंगाली लोगों की उत्पत्ति पामीर क्षेत्र के किस प्राचीन समूह से हुई थी?

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?