Among $Al_2O_3, SiO_2, P_2O_3$ and $SO_2$ the correct order of acid strength is

Question

( A ) $Al_2O_3 < SiO_2 < P_2O_3 < SO_2$
( B ) $Al_2O_3 < SiO_2 < SO_2 < P_2O_3$
( C ) $SO_2 < P_2O_3 < SiO_2 < Al_2O_3$
( D ) $SiO_2 < SO_2 < Al_2O_3 < P_2O_3$