Answer
$(i) = OH^-$
$(ii) = H_3PO_4$
Work Step by Step
Write the reactions where the bases reacts with water.
$(i) O^{2-} + H_2O --> 2OH^- $
$(ii) {H_2PO_4}^- + H_2O --> H_3PO_4 + OH^-$
*Analyzing those reactions, we will find that $OH^-$ and $H_3PO4 $ are the conjugated acids.