35) At the county fair, Carrie and Sam climbed up on the carousel horses. Around and around they went; the horses also bobbed up and down. When they got off of the carousel, Carrie told Sam they had been accelerating during their ride. Sam disagreed; they had been moving at a constant speed. Whose response is fully correct, and why?

A) Carrie is, because the carousel changed speed when it started and stopped.
B) Sam is, because the horses never moved from their position on the carousel.
C) Carrie is, because velocity includes speed plus direction, and both changed.
D) Sam is, they did not accelerate since their speed remained constant for the ride.