उस पहले गुर्जर प्रतिहार शासक की पहचान कीजिए जिसने अरब आक्रमणकारियों को सफलतापूर्वक पराजित 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?