$\mathrm{B}(\mathrm{OH}{)}_3+\mathrm{NaOH}\rightleftharpoons {\mathrm{NaBO}}_2+\mathrm{Na}\left[\mathrm{B}(\mathrm{OH}{)}_4\right]+{\mathrm{H}}_2\mathrm{O}$

How can this reaction be made to proceed in forward direction?

$\mathrm{B}(\mathrm{OH}{)}_3+\mathrm{NaOH}\rightleftharpoons {\mathrm{NaBO}}_2+\mathrm{Na}{\left[\mathrm{B}(\mathrm{OH}{)}_4\right]}^{-}+{\mathrm{H}}_2\mathrm{O}$

The addition of cis-1,2-diols to the reaction flask causes them to consume ${\left[\mathrm{B}(\mathrm{OH}{)}_4\right]}^{-}$, which proceed the reaction in the forward direction.

Correct option is A.