The radius of the second orbit of an electron in hydrogen atom is 2.116 ${\mathrm{A}}^0$. The de-Broglie wavelength associated with this electron in this orbit would be

• A

  $6.64 {\mathrm{A}}^0$

• B

  $1.058{\mathrm{A}}^0$

• C

  $20116 {\mathrm{A}}^0$

• D

  $13.28 {\mathrm{A}}^0$