Which type of solution contains a liquid solute and a liquid solvent?

The type of solution that contains both a liquid solute and a liquid solvent is known as an emulsion. An emulsion is a system where small droplets of one liquid are dispersed throughout another liquid with which it is immiscible, such as oil and water. In this case, the liquid solute might be oil, and the liquid solvent could be water, or vice versa. This unique interaction between the two liquids typically requires an emulsifying agent to stabilize the mixture, preventing the two liquids from separating.

When considering other options, a gas mixture consists of different gases mixed together, with no liquid components involved. An aqueous solution contains a solute that is dissolved in water, which is a liquid solvent, but does not fit the definition of having a liquid solute if we assume common solutes (like salts, sugars, etc.) that are solids in nature. An oil solution may refer to a solute dissolved in an oil solvent but lacks the combination of two liquid phases that defines an emulsion. Thus, emulsion is the only correct choice for a solution that includes both a liquid solute and a liquid solvent.