After Reading the Paragraph Below, Answer the Question(s) That Follow(s)

After reading the paragraph below, answer the question(s) that follow(s) .
A student conducts the following experiment at home: a bunch of unripe bananas are placed in an open bowl on the table; a second bunch of unripe bananas of equal size and number is placed in an adjacent bowl, but the bowl and fruit are sealed in plastic wrap.
-The gaseous hormone that is contributing to the ripening of the bananas is

A) cytokinin.
B) acetylene.
C) ethylene.
D) gibberellin.