Correct Response: B. Water droplets dispersed in air meet the requirements of an aerosol. An aerosol is a suspension of particles dispersed in air or gas. A is incorrect because a solution is a mixture in which a minor component is uniformly distributed within a major component. In this case there is only one substance, water, so fog cannot correctly be termed a solution. C is incorrect because foam refers to a mass of small bubbles that are typically at the top of a liquid. These bubbles are formed by any of a number of processes, including agitation or fermentation. D is incorrect because an emulsion is a fine dispersion of minute droplets of one liquid in another in which it is not miscible. Since water is the only substance in fog, fog cannot correctly be termed an emulsion.
