The Dealey Electric Group produces light bulbs that are used in refrigerator manufacturing. Currently, only three other companies produce bulbs used in the production of refrigerators, with Dealey as the leader in market share.
In this case, Dealey Electric Group would be considered:

A. a monopoly.
B. involved in perfect competition.
C. involved in monopolistic competition.
D. involved in a perfect oligopoly.
E. an oligopoly.