The correct options are
A 2O3⟶3O2
B 4KClO3⟶3KClO4+KCl
C 2H2O2⟶2H2O+O2
D 2KO2+2H2O⟶4KOH+3O2
The various redox reactions are given below:
2O3⟶3O2
+2/-2 0
4KClO3⟶3KClO4+KCl
+5 +7 -1
2H2O2⟶2H2O+O2
-1 -2 0
2KO2+2H2O⟶4KOH+3O2
-1/2 -2 0
Thus, we can see that all the above reactions are disproportionation reactions.