निम्नलिखित में से किस वेद को भारतीय विरासत में सबसे प्रारंभिक या सबसे प्राचीन साहित्यिक रचना माना जाता है?

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?