what is the coordination number of cations in antifluorite structure?

A) 4
B) 6
C) 8
D) 12
Why is the Answer not 8?

Dear student...In antifluorite, of formula A2X, the coordination numbers of cation and anion must be in the ratio of 1:2. Since the cations occupy tetrahedral sites, the anion coordination number must be eight.. Antifluoride structure has opposite arrangement of inos than fluorite structure. For antifluorite structure Coordination number of cation = 4 Coordination number of anion = 8 ... Ans is A..... Regards