An airplane has a gun that fires bullets straight ahead at the speed of 600 m/h when tested on the ground while the plane is stationary. The plane then flies east at 600 m/h. Explain whether each of the following is possible for the pilot to measure:
A. When fired directly ahead the bullets move eastward at a speed of 1200 m/h
B. When fired in the opposite direction, the bullets drop vertically downward
C. If fired vertically downward, the bullets move eastward at 600 m/h while they fall.