Bill and His Daughter Susan Are Both Standing on Identical

Multiple Choice

Bill and his daughter Susan are both standing on identical skateboards (with really good frictionless ball bearings) , initially at rest. Bill weighs three times as much as Susan. Bill pushes
Horizontally on Susan's back, causing Susan to start moving away from Bill. Just after Bill stops
Pushing,

A) Susan and Bill are moving away from each other, and Susan's speed is one-third that of Bill.
B) Susan and Bill are moving away from each other, with equal speeds.
C) Susan and Bill are moving away from each other, and Susan's speed is three times that of Bill.
D) Susan is moving away from Bill, and Bill is stationary.