In the Bohr model of a hydrogen atom, the centripetal force is furnished by the Coulomb attraction between the proton and the electrons. If `a_(0)` is the radius of the ground state orbit, `m` is the mass and `e` is the charge on the electron and `e_(0)` is the vacuum permittivity, the speed of the electron is
A. zero
B. `(e)/(sqrt(epsilon_(0)a_(0)m))`
C. `(e)/(sqrt(4piepsilon_(0)a_(0)m))`
D. `(sqrt(4piepsilon_(0)a_(0)m))/(e)`