Sarah Hartshorne answers our lingering questions about her memoir You Wanna Be on Top? , which recounts her experience as the only plus-size contestant on America’s Next Top Model cycle nine. Photo: The CW Sarah Hartshorne was a Boston University sophomore when she heard that America’s Next Top Model was holding a casting call for its upcoming season at the nearby Prudential Center. With the encouragement of a few friends, she auditioned, was accepted to cycle (as the series refers to its