$\begin{array}{l}{\mathrm{B}}_2{\mathrm{H}}_6+{\mathrm{H}}_2\mathrm{O}\stackrel{ }{\to }\mathrm{X}+{\mathrm{H}}_2;\\ {\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7+{\mathrm{H}}_2\mathrm{O}\stackrel{ }{\to }\mathrm{Y}+\mathrm{NaOH};\end{array}$

X and Y are

• A

  ${\mathrm{H}}_3{\mathrm{BO}}_3,{\mathrm{H}}_3{\mathrm{BO}}_3$

• B

  ${\mathrm{HBO}}_2,{\mathrm{H}}_3{\mathrm{BO}}_3$

• C

  ${\mathrm{H}}_3{\mathrm{BO}}_3,{\mathrm{HBO}}_2$

• D

  ${\mathrm{H}}_2{\mathrm{B}}_4{\mathrm{O}}_7 , {\mathrm{H}}_3{\mathrm{BO}}_3$