Which pair of oxyacids of phosphorus contains ' $\mathrm{P}-\mathrm{H}^{\prime}$ bonds?

• A

  $\mathrm{H}_{3} \mathrm{PO}_{4}, \mathrm{H}_{3} \mathrm{PO}_{3}$
• B

  $\mathrm{H}_{3} \mathrm{PO}_{5}, \mathrm{H}_{4} \mathrm{P}_{2} \mathrm{O}_{7}$
• Correct answer
  C

  $\mathrm{H}_{3} \mathrm{PO}_{3}, \mathrm{H}_{3} \mathrm{PO}_{2}$
• D

  $\mathrm{H}_{3} \mathrm{PO}_{2}, \mathrm{HPO}_{3}$

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