Correct Answer - B
Raw materials for cement-limestone, clay, gypsum. Cement is a dirty greyish heavy powder contaning calcium aluminates and silicates. Gypsum `(CaSO_(4).5H_(2)O)` is added to the components to increase the setting time of cement so that it gets sufficiently hardened. Setting of cement is an exothermic process and involves hydration of calcium aluminates and silicates.