In the extraction of aluminium Process X : employed for red bauxite .
WEBThe correct answer is Bayer applied red bauxite to remove iron oxide. While Serpeck's process: applied for white bauxite to remove SiO2. Using Serpeck's method, white bauxite is beneficially processed. It includes purging impurities. SiO2+2C→Si+2CO Hence the correct option is B.