Velma Is in a Train Moving Eastward at 70 M/s

Multiple Choice

Velma is in a train moving eastward at 70 m/s. She throws a ball toward the rear of the train, throwing it at her normal "throwing speed" of 20 m/s. The ball's velocity relative to Mort, who is standing beside the tracks, is

A) 50 m/s westward.
B) 90 m/s eastward.
C) 20 m/s eastward.
D) 20 m/s westward.
E) 50 m/s eastward.