It consists of Guiana Highlands in the North, Brazilian Highlands in the center, and Patagonia Highlands in the South. What is it? A. Southern mountains
B. Eastern river basin
C. Central plain
D. The Eastern Highlands

Answer collision and mountain formation;

Magma forms by partial melting of upper mantle and crust. partial melt means that only a fraction of the available material forms a melt, and that the remainder stays solid. the partial melt rises because of its lower density and ascends through he crust. this is so conclusive mean the answer would be magma igneous rocks or balistic magma.