Answer :
Urban sprawl basically means urbanization so it is correct. Cities like Los Angeles are already urbanized, heavily, which means urban sprawl won't occur. On the other hand, upward growth is bound to happen beacuse it will keep growing and growing and spreading like large cities usually do.
I think the correct answer is true. Cities that have available space in surrounding areas, such as Los Angeles, are likely to experience upward growth rather than urban sprawl because there are more space for people to stay and build homes. Hope this answers the question.