Following reaction (s) is /are involved in the iodometric estimation

Options

A. `Cr_(2)O_(7)^(2-) +H^(+)+I^(-) to 2Cr^(3+)+I_(2),I_(2)+S_(2)O_(3)^(2-)toS_(4)O_(6)^(2-)+I^(-)`
B. `MnO_(4)^(-)+H^(+)+I^(-) toMn^(2+)+I_(2),I_(2)+S_(2)O_(3)^(2-)toS_(4)O_(6)^(2-)+I^(-)`
C. `MnO_(4)^(-)+OH^(-)+I^(-)to MnO^(2)+I_(2),I_(2)+S_(2)O_(3)^(2-) to S_(4)O_(6)^(2-)+I^(-)`
D. `Cr_(2)O_(7)^(2-)+OH^(-)+I^(-) to 2Cr^(3+)+I_(2),I_(2)+S_(2)O_(3)^(2-)toS_(4)O_(6)^(2-)+I^(-)`

Answer

AB