Dihydrogen of high purity $(>99.95 \%)$ is obtained through:

• A
  the electrolysis of warm $Ba(OH)_2$ solution using $Ni$ electrodes.
• B
  the reaction of $Zn$ with dilute $HCl$.
• C
  the electrolysis of brine solution.
• D
  the electrolysis of acidified water using $Pt$ electrodes.