Which of the following is not an aerosol?

Among the given options, mud is not an aerosol.

An aerosol is a suspension of fine solid particles or liquid droplets, in the air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog, dust, forest exudates and geyser steam. Examples of anthropogenic aerosols are haze, particulate air pollutants, and smoke.