Answer each of the following questions as either true or false. For a statement to be "true," it must always be true. If there is at least one case where the statement is not true, answer "false." You must justify each answer with an appropriate explanation or counterexample (which may include a relevant diagram).
(a) In an oligopoly model where firms choose prices for a homogeneous product and have constant (but different) marginal costs, there is a Bertrand-Nash equilibrium in which both firms make sales to customers.
(b) In an oligopoly model where firms choose quantities for a homogeneous product and have constant (and identical) marginal costs, an increase in the number of firms causes the market price to fall.
(c) For both perfect competitors and monopolies, a firm’s marginal revenue is equal to the price of the good that the firm sells: if corn costs $6 per bushel and the firm sells one more unit, then revenue rises by $6.
