The name of the grasslands in Southern Africa is Velds. The term "veld" is derived from the Afrikaans word for "field" or "pasture". These grasslands are characterized by tall grasses, scattered trees, and a diverse range of wildlife. The Velds are an important habitat for many species, including herbivores like zebras and wildebeests, as well as predators like lions and cheetahs.

Option 1, Savannah, refers to a different type of grassland found in tropical regions with distinct wet and dry seasons, such as in Africa and South America.

Option 2, Pampas, refers to the grasslands found in South America, particularly in Argentina and Uruguay.

Option 4, Prairies, refers to the grasslands of North America, primarily found in the central part of the continent.

Therefore, the correct answer is option 3, Velds.