# Portland cement does not contain :

$(a)\;Ca_3Al_2O_6\qquad(b)\;Ca_3SiO_3\qquad(c)\;Ca_2SiO_4\qquad(d)\;Ca_3(PO_4)_2$

Portland cement does not contain $Ca_3(PO_4)_2$
Hence (d) is the correct answer.