The correct answer is option 2 - The account of Megasthenes.
Megasthenes was a Greek ambassador who visited India during the Mauryan period and wrote detailed accounts of his observations. His work, known as the Indika, provides valuable information on various aspects of Mauryan administration, including the municipal administration.
Option 1, The Arthasastra of Kautilya, is a text written by Chanakya (also known as Kautilya) during the Mauryan period. While it discusses topics related to governance and administration, it does not specifically provide a detailed account of the municipal administration.
Option 3, The Mudrarakshasa, is a Sanskrit play written by Vishakhadatta, which is based on the political intrigue during the rule of Chandragupta Maurya. It does not provide a detailed account of the municipal administration.
Option 4, Mauryan inscriptions, are ancient inscriptions found on pillars and rocks from the Mauryan period. While these inscriptions provide valuable information about the Mauryan Empire and its accomplishments, they do not specifically focus on the municipal administration.
Therefore, the correct choice for a detailed account of the municipal administration of Mauryas is option 2 -