A.4Fe(OH)2+O2+2H2O=4Fe(OH)3 B.4Co(OH)2+O2+2H2O=4Co(OH)3 C.Ni(OH)2+O2+2H2O=4Ni(OH)3 D.2Co(OH)2+ClO-+H2O=2Co(OH)3+Cl-