प्रसिद्ध बौद्ध ग्रंथ "मिलिन्दपन्हो" मूल रूप से किस भाषा में लिखा गया 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?