Answer: d. Central Asia
Explanation:
The majority of people in North India, Pakistan, Bangladesh and the area around these countries speak the Indo-Aryan language.
Around 2000BC in what became known as the Indo-Aryan Migration, Indo-Aryan groups migrated into Iran, India and Anatolia where they precipitated a change in the languages spoken in the area.
These groups originated in Central Asia around an area in modern day Russia and Kazakhstan.