The number of $S=O$ and $S-OH$ bonds present in peroxodisulphuric acid $(H_2S_2O_8)$ and pyrosulphuric acid $(H_2S_2O_7)$ respectively are:

• A
  ($2$ and $2$) and ($2$ and $2$)
• B
  ($2$ and $4$) and ($2$ and $4$)
• C
  ($4$ and $2$) and ($2$ and $4$)
• D
  ($4$ and $2$) and ($4$ and $2$)