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

a. an oligopoly.
b. a monopoly.
c. involved in monopolistic competition.
d. involved in perfect competition.
e. involved in a perfect oligopoly.