The correct option is C Weathering of rocks like granite and gneiss
Red Soil is formed by the weathering of igneous rocks like granite and metamorphic rocks like gneiss. The soil appears red due to the presence of iron and its oxides. Red soil is found in the southern districts of Karnataka like Tumakuru, Bengaluru, Ramnagar, Chikballapur, Kolar, Chamrajnagar, Mandya and Mysuru.