C-10-Q067mediumsingle_mcqThe formula of cryolite is—aNa3AlF6\mathrm{Na_3AlF_6}Na3AlF6bNaAlO2\mathrm{NaAlO_2}NaAlO2cAlF3\mathrm{AlF_3}AlF3dAl2(SO4)3\mathrm{Al_2(SO_4)_3}Al2(SO4)3