The radius of which of the following orbit is same

Options

A. `He^(2+) (n=2)`
B. `Li^(2+) (n=2)`
C. `Li^(2+) (n=3)`
D. `Be^(3+) (n=2)`

Answer

D

Explanation

`r =(n^2)/(z) (0.529)A^@`