The Assumption(s) Made to Construct a Kinked-Demand Oligopoly Model Is

The assumption(s) made to construct a kinked-demand oligopoly model is (are) that:

A) all firms in the industry will ignore the price changes made by any one firm.
B) any price decrease will be ignored, but price increases will be followed.
C) all firms will follow a price decrease but will ignore any price increase.
D) all price changes made by any firm will be followed by all of the other firms.
E) price can go up, but it cannot go down.