The number of $\mathrm{S}=\mathrm{O}$ bonds present in sulphurous acid, peroxodisulphuric acid and pyrosulphuric acid, respectively are :

• A

  $1,4$ and $3$
• Correct answer
  B

  $1,4$ and $4$
• C

  $2,3$ and $4$
• D

  $2,4$ and $3$

Hence, the correct answer is option: 'B'.