C-08-Q104mediumsingle_mcqChemical formula of limestone is —aCaSOX4\ce{CaSO4}CaSOX4bCaCOX3\ce{CaCO3}CaCOX3cSiOX2\ce{SiO2}SiOX2dFeX2OX3\ce{Fe2O3}FeX2OX