This type of intermolecular force occurs when two molecules attract due to their electron density shifting to create opposite short-lived partial positives and negatives?

London dispersion forces

Explanation:

The London dispersion force is the weakest kind of intermolecular force. The London dispersion force is a temporary attractive force that occurs 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.

These London dispersion forces are mostly seen in the halogens (e.g., Cl2 and I2), the noble gases (e.g., Xe and Ar), and in many non-polar molecules, such as carbon dioxide and propane. London dispersion forces are part of the van der Waals forces, and are very weak intermolecular attractions.

c, liquids evaporate, creating a gas