For the given question above, I think there is an associated choice of answer for it. However, the answer for this is London Dispersion Forces. <span>Dipole-dipole forces and hydrogen bonding are much stronger, leading to higher melting and boiling points.</span>
Kinetic energy, KE, is modeled by the formula

, where m is the mass in kg and v is the velocity in m/s.
In this scenario, mass and one-half are constant but the velocity changes.
You can see that by squaring twice the velocity, that is equal to four times the original KE. Therefore, the answer is 4k.
I would have to say B failed because I think I read something about it being only 2law not 3