The correct option is
A AlCl3Al+3NaOH⟶Al(OH)3+3Na+
(white ppt.)
Al(OH)3+NaOH⟶Na+[Al(OH)4]− (Compound B)
(soluble complex)
Al(OH)3+3HCl⟶AlCl3+3H2O
(dil) (Compound C)
2Al(OH)3Strong−−−−−−→heating △Al2O3+3H2O
↓
(used to extract metals)
Compound D=Al2O3
Compound A=Al(OH)3
Compound B=Na+[Al(OH)4]−
Compound C=AlCl3
Compound D=Al2O3