Two firms produce high quality aloha shirts: Hawaiian Wear (HW) and Island Wear (IW). Each firm has the same cost function given by TC = 20Q + Q2. The market demand for aloha shirts is P = 200 - 2QT where QT is the total output of the two firms. If each firm acts to maximize its profits, taking its rival's output as given (i.e., the firms behave as Cournot oligopolists), what will the equilibrium level of output be for each firm?
a. QHW = 18 and QIW = 18
b. QHW = 30 and QIW = 30
c. QHW = 45 and QIW = 45
d. QHW = 22.5 and QIW = 22.5