Malbaby and cpgatbyu as correct. ... The quiz creator incorrectly mixed up "continental" with Contiguous United States. ... The continental United States contains all states. but Hawaii. ... The Contiguous United States contains "the lower 48."
I changed the question from continental to lower 48. However, the Miami urban area is about 20 times as populous as Anchorage, so I think @cpgatbyu's comment is a little misleading. Clearly its possible for Miami to be a major city and Anchorage not to be.
No it is not. A city is an agglomeration of different urban functions that operate as a whole. By your definition any classical city (notice the word city here) would not be a city since they had no official borders. In many developing countries there would still not be any cities because again no borders have been formalized. Yet clearly all these cities exist(ed). Your definition of a city is thus extremely reductionist and does not allow for any proper analysis.
I agree with accepting "Canadian bacon" as an answer.