For each of the following statements, state whether it is true or false? If false, briefly explain.
(a) With only two goods, if one good is a "bad" and the other is a "good", then the indifference curves are upward sloping.
(b) A Giffen good can be a normal good.
(c) If average cost is decreasing as output increases, then marginal cost is smaller than the average cost.
(d) In a Cournot duopoly, in the equilibrium, the total quantity is less than that of a monopoly.