Which geographical factor attracted traders of east africa leading to the creation of the swahili culture

The correct answer should be the following one - the coastal region along the Southeast African border, which had port facilities to support trade.
This is the geographical factor that attracted traders of east Africa to this location, which in turn led to the creation of the Swahili culture. Swahili refers to the culture of the Bantu people in Africa, in countries such as Tanzania, Uganda, Mozambique, etc.