Which is the best example of Newton's Second Law of Motion?

A student has on roller skates and he decides to push against the railing. He immediately begins to roll backwards.
A small ball and a larger ball with greater mass are dropped from a roof. The larger ball strikes the ground with greater force than the smaller ball.
A baseball player hits a baseball that is pitched to him. The ball immediately soars back in the direction of the pitcher.
You are riding in a car that makes a quick right turn. You immediately slide across the back seat.