Which Alteration of the Assumptions Behind the Bertrand Model Can

Multiple Choice

Which alteration of the assumptions behind the Bertrand model can help avoid the Bertrand Paradox (that an outcome resembling perfect competition may arise with even as few as two firms) ?

A) assume firms have limited capacities.
B) assume firms produce differentiated rather than homogeneous products.
C) assume firms play repeatedly and thus may collude.
D) all of the above.