The Figure Above Shows the Market for Airplanes

The figure above shows the market for airplanes.
-Suppose the airplane market is an oligopoly.According to the figure above,the quantity produced can range as high as ________ planes per week and as low as ________ planes per week.

A) 10; 4
B) 12; 6
C) 6; 0
D) 12; 0
E) None of the above answers is correct.