Which of the following gas is/are obtained by electrolysis of acidified water using platinum electrodes?

• A

  ${\mathrm{H}}_2$

• B

  ${\mathrm{O}}_2$

• C

  ${\mathrm{N}}_2$

• D

  ${\mathrm{H}}_2\text{ and }{\mathrm{O}}_2$