When objects are far away they lack contrast, detail, and sharpness of focus because of the interference of air. artists take advantage of this when they use the process called: a. cross-hatching b. highlight c. atmospheric perspective d. chiaroscuro e. isometric perspective?

The air is part of the atmosphere, so it'll have to be the process of Atmospheric Perspective.

Option C. Atmospheric perspective.

Explanation:

The Atmospheric perspective, or Aerial perspective, is a method of creating the illusion of depth, or recession, in a painting or drawing by modulating color to simulate changes effected by the atmosphere on the colors of things seen at a distance.

Just as stated in question provided, atmospheric perspective is the technique used by artists to depict the effects of the atmospheric air on the appearance of an object as it is viewed from a distance.