The correct option is D subsistence farming. One of the innovations spread to Southern Africa as the result of the migration of Bantu-speaking people, which was a series of migration of the proto-Bantu language speaking group from central Africa across the sub-Sahara Africa, was the introduction of new farming techniques.
Agriculture and farming techniques improved thanks to the ability of Bantu-speakers to reproduce and expand more quickly, surviving thanks to the plants and animals spread and cultivated by them.
