In the iodometric estimation in the laboratory which process is involved?

Options

A. `Cr_2O_7^(2-)+H^(o+)+I^(ɵ)to2Cr^(3+)I_2`
`I_2+S_2O_3^(2-)toS_4O_6^(4-)+I^(ɵ)`
B. `MnO_4^(ɵ)+H^(o+)+I^(ɵ)toMn^(2+)+I_2`
`I_2+S_2O_3^(ɵ)toS_4O_6^(2-)I^(ɵ)`
C. `MnO_4^(ɵ)+OH^(ɵ)+I^(ɵ)toMnO_2+I_2`
`I_2+S_2O_3^(2-)toS_4O_6^(2-)+I^(ɵ)`
D. `Cr_2O_7^(2-)+OH^(ɵ)+I^(ɵ)to2Cr^(3+)+I_2`
`I_2+S_2O_3^(2-)toS_4O_6^(2-)+I^(ɵ)`

Answer

a,b