The stupas at Bharhut and Sanchi were originally established during the reign of —

The correct answer is Ashoka. The earliest cores of the Sanchi and Bharhut stupas are traditionally associated with Ashoka, although their monumental railings, gateways and much visible decoration belong to later Shunga and subsequent phases. A strong answer should connect the term or object with its precise source, location, ruler, regnal context, and administrative function.