In the Kinked Demand Curve Model, the Kink in the Demand

In the kinked demand curve model, the kink in the demand curve arises because:

A) the elasticity of the demand curve changes at the equilibrium output.
B) there are no barriers to entry or exit in the industry.
C) the demand for the good is unstable and keeps changing.
D) the products sold by each firm in the market are different.