फ़तेहगढ़ साहिब का एक महत्वपूर्ण पुरातात्विक स्थल संघोल, किस प्राचीन संस्कृति से जुड़ा हुआ 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?