Velma Is in a Train Moving Eastward at 20 M/s

Multiple Choice

Velma is in a train moving eastward at 20 m/s. She throws a ball toward the rear of the train, throwing it at her normal "throwing speed" of 20 m/s. What is Mort's observation, regarding the ball?

A) It moves westward at 40 m/s.
B) It moves eastward at 40 m/s.
C) It moves westward at 20 m/s.
D) It falls straight down.
E) It moves eastward at the same speed of the train, just keeping up with the train.