The correct answer is 6) Bactria
The farthest reaches of Alexander conquests is indicated in the map with number 6. This indicates the region of Bactra, which is a territory situated in Central Asia, located between the Hindu Kush to the south, and the Oxus river to the north; its capital was the city of Balh (Bactra or Zaraspa). Today that territory corresponds to several nations, northern Afghanistan, southern Uzbekistan, and Tajikistan.
The classic language of Bactriana was an Indo-European language of the Indo-Iranian sub-family, the Bactrian language, but there were a lot of Greeks living there in times of Alejandro and Seleuco, his successor in that region.
In Bactria he got married with Roxana, and they had a child, but they and all the members of Alexander family were murdered after his death.