Suppose That Firms $A$ And $B$ Are Cournot Duopolists in the Salt Industry

Multiple Choice

Suppose that firms $A$ and $B$ are Cournot duopolists in the salt industry. The market demand curve can be specified as $P = 200 - Q _ { A } - Q _ { B }$ . The marginal cost to each firm is $\$ 40$ . What is firm $B$ 's profit-maximizing quantity when firm A produces an arbitrary output $Q _ { A }$ ?

A) $Q _ { B } = 160 - Q _ { A }$ .
B) $Q _ { B } = 160 - 2 Q _ { A }$ .
C) $Q _ { B } = 80 - Q _ { A }$ .
D) $Q _ { B } = 80 - \frac { 1 } { 2 } Q _ { A }$ .