A Passenger at Rest on a Flatbed Train Car Fires

Multiple Choice

A passenger at rest on a flatbed train car fires a bullet straight up. The event is viewed by observers at rest on the station platform as the train moves past the platform with constant velocity. What is the trajectory of the bullet as described by the observers on the platform?

A) a straight horizontal path in the direction of the train's velocity
B) a straight vertical path up and down
C) a circular path centered on the gun
D) a straight diagonal path
E) a parabolic path