The correct answer is A, as Greek city-states established colonies to reduce overpopulation.
It was necessary to search for new lands due to the land grabbing by the aristocracy and the demographic increase of the population. Added to this was the traditional principle of inheritance that required the division of land in equal parts for the heirs, making the lots distributed smaller and smaller. All this produced the so-called "estnokhoría", which was the scarcity of land, which demanded solutions such as looking for colonial lands far from their city of origin.