A small ball is hung by a string from the ceiling of a train car, so that the ball hangs vertically. Moving from rest, the train car accelerates forward, and continues to accelerate. A team of scientists observes the behavior of the ball from various locations. From which scientist's frame of reference does the motion of the ball appear to violate Newton’s Law of Inertia? A.

on the train station platform

B.

inside of the train car

C.

in a second train car moving with constant speed in the same direction as the first train

D.

in a third train car moving with constant speed opposite the direction of the first train