If the wave number of radiation emitted for the electron transition from an excited state to ground state of hydrogen is $\frac{5 \mathrm{x}}{36} \mathrm{~m}^{-1}$, the wave number of radiation absorbed for the electron transition from the above excited state to next immediate excited state in $\mathrm{m}^{-1}$ is:

• Correct answer
  A

  $\frac{7 x}{144}$
• B

  $\frac{21 x}{100}$
• C

  $\frac{16 x}{225}$
• D

  $\frac{5 x}{36}$

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