Which of the following describes dispersion forces?

Dispersion forces, also known as London dispersion forces, arise from the temporary fluctuations in electron distribution within nonpolar molecules. These fluctuations can create instantaneous dipoles, which induce dipoles in neighboring molecules, leading to an attraction. Since dispersion forces are present in all molecules—though they are the only type of intermolecular force in nonpolar molecules—they predominantly characterize the interactions between nonpolar substances.

These forces are relatively weak compared to other types of intermolecular forces such as dipole-dipole interactions and hydrogen bonding, which occur in polar molecules. Therefore, the correct answer highlights the nature of dispersion forces pertaining specifically to nonpolar molecules, making it the accurate description of these interactions.

In contrast, polar molecules experience stronger intermolecular attractions due to their permanent dipoles, and ionic compounds exhibit even stronger attractions due to the ionic bonds between charged particles; therefore, options describing those interactions are not aligned with dispersion forces.