Imagine a neutral particle of same mass m as electron revolving around a proton of mass `M_(p)` only under newton's gravitational force. Assuming Bohr's quantum condition, the radius of electron orbit is given by:

Options

A. `(n^(2)h^(2))/(pim^(2)GM_(p))`
B. `(n^(2)h^(2))/(4pi^(2)m^(2)GM_(p))`
C. `(GM_(p)n^(2)h^(2))/(4pi^(2)m^(2))`
D. `(nhGM_(p))/(4pim)`