The strength of London forces depends on size of

Explanation

Option B is correct since the London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. This force is sometimes called an induced dipole-induced dipole attraction. The greater the size of the electron cloud, the greater will be the asymmetrical distribution of electrons and the greater will be the tendency of a molecule to be charged. Option A is incorrect since the size of all electrons is the same. Option C is incorrect since the size of the lone pair on an atom is also the same. Option D is incorrect since the size of the poles of atoms does not affect the strength of London forces.