Correct Answer - C
`OH^(-)` can attack any of the three CHO groups, but nucleophillic addition of `.^(-)OH` ions occurs on that `CHO` group which is located at para-positions with respect to the order. This is because electron withdrawing groups facilitate the release of hydride ions from the intermediate,
The `p-CHO` group is oxidised while the `m-CHO` group is reduced.