An alloy of Copper , Silver and Gold is found to have Copper constituting the C.C.P lattice. If Silver atoms occupy the edge centres and Gold is present at body centre , the alloy will have the formula:

Question

$(a)\;Cu_4 Ag_2 Au\qquad(b)\;Cu_4Ag_4 Au\qquad(c)\;Cu_4 Ag_3 Au\qquad(d)\;Cu Ag Au$