The correct options are
A X=Na, Y=H2O, Z=SO2, P=H2SO3 C X=K, Y=H2O, Z=SO2, P=H2SO32Na+2H2O→2NaOH+H2(X) (Y)(or)2K+2H2O→2KOH+H2(X) (Y)(or)S+O2→SO2 (Z)SO2+H2O→H2SO3(Z) (Y) (P)
Hence, X can be either sodium or potassium. Y is water while Z is SO2 and P is sulphurous acid.