Concept:Volcanic mountains are formed by lava and volcanic activity, not by erosion.Explanation:Examples of volcanic mountains include Cotopaxi of Ecuador, Fuji of Japan, and Midcrop of Sumatra.These peaks are built from erupted lava and ash.Monadnock of the USA, however, is a residual mountain formed by erosion, not by volcanic action.Since it is not a volcanic mountain, it is the correct exception.Answer:D. Monadnock of USA