If $\mathrm{\alpha }=\frac{\mathrm{h}}{4{\mathrm{\pi }}^2\mathrm{m}{\mathrm{e}}^2},$ then the correct expression to calculate of the circumference of the first orbit of hydrogen atom is

• A

  $\sqrt{4}\mathrm{\pi }\mathrm{h\alpha }$
• B

  $\sqrt{2}\mathrm{\pi }\mathrm{h\alpha }$
• C

  $\sqrt{4{\mathrm{h}}^2}\mathrm{\pi \alpha }$
• Correct answer
  D

  Both A and C

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