when Boron is reacted with Conc ${\mathrm{H}}_2{\mathrm{SO}}_4$, the gaseous product is 

• A

  ${\mathrm{B}}_2{\mathrm{O}}_3$

• B

  ${\mathrm{SO}}_2$

• C

  ${\mathrm{O}}_2$

• D

  ${\mathrm{SO}}_3$