The book 'Indica', describing India in the time of Chandragupta Maurya, was written by:

Megasthenes was a Greek historian and diplomat. He was sent as the ambassador of Seleucus I Nicator, the Greek ruler of the eastern part of Alexander's empire, to the court of Chandragupta Maurya at Pataliputra around 302 BCE. He stayed in India for several years and wrote a book called "Indica" describing the country.

The original "Indica" has been lost. Its contents are known only through quotations and summaries in the works of later Greek and Roman writers, such as Strabo, Diodorus and Arrian. Some of Megasthenes' statements are exaggerated or incorrect, but his account is still a valuable source on Mauryan India.

Important information from the "Indica":

• A description of Pataliputra as a large city surrounded by a wooden wall with 64 gates and 570 towers, and a moat.
• The administration of the city by six committees (boards) of five members each, dealing with industries, foreigners, registration of births and deaths, trade, manufactured goods and the collection of taxes.

Indian society was divided into seven classes: philosophers, farmers, soldiers, herdsmen, artisans, magistrates and councillors. This was his own classification and does not match the varna system.

He claimed that there were no slaves in India and that famines were rare, statements that historians question.

Background: after Alexander's death, Seleucus tried to reconquer north-western India but was defeated by Chandragupta Maurya around 305 BCE. In the treaty that followed, Seleucus gave Chandragupta the regions of Arachosia (Kandahar), Gedrosia (Balochistan) and Paropamisadae (Kabul), and Chandragupta gave him 500 war elephants. A marriage alliance may also have been made.

Another important source on the Mauryas is the "Arthashastra" of Kautilya (Chanakya), a treatise on statecraft and administration.

Why not the other options?

• ✗Fa-Hien (Faxian) was a Chinese pilgrim who visited India during the Gupta period.
• ✗Kautilya wrote the "Arthashastra".
• ✗Ptolemy was a geographer who wrote "Geographia".