An elevator carries a passenger standing on a bathroom scale. The elevator starts from rest at the ground floor, accelerates upward until it reaches its cruising speed, then travels upward at that constant speed, and finally slows to a stop at the top floor. During which part of the ride does the scale display its greatest reading?
(a) The scale shows the same reading during all three parts of the ride.
(b) While the elevator is moving upward at constant speed.
(c) While the elevator is accelerating upward away from the ground floor.
(d) While the elevator is slowing down as it approaches the top floor.