Final answer:
The intermolecular force that least affects boiling point is van der Waals forces, more specifically, London dispersion forces, as these are the weakest and most temporary. So the correct option is B.
Step-by-step explanation:
The intermolecular force that would affect the boiling point the least is van der Waals forces, specifically London dispersion forces. These are the weakest form of intermolecular attraction and are less influential in determining a substance's boiling point compared to the stronger forces such as hydrogen bonding, dipole-dipole interactions, and ionic bonding. London dispersion forces are temporary, caused by fluctuations in electron distribution, and are more significant in larger atoms or molecules. Hence, among the options provided, the intermolecular force affecting the boiling point the least would be B. Van der Waals forces.