The coagulating power of electrolytes having ions $Na^+, Al^{3+}$ and $Ba^{2+}$ for arsenic sulphide sol increases in the order :

Question

( A ) $Ba^{2+} < Na^+ < Al^{3+}$
( B ) $Al^{3+} < Na^+ < Ba^{2+}$
( C ) $Al^{3+} < Ba^{2+} < Na^+$
( D ) $Na^+ < Ba^{2+} < Al^{3+}$