According to Bohr's atomic theory, which of the following is correct ?

Options

A. Potential energy of electron `propZ^(2)/n^(2)`
B. The product of velocity of electron and principal quantum number (n) `prop-Z^(2)`
C. Frequency fo revolution of electron in an orbit `propZ^(2)/n^(3)`
D. Coulombic force of attraction on the electron `propZ^(2)/n^(2)`