The correct answer is Great Zimbabwe
These buildings were sometimes even over 5 meters long and were made out of bricks that were stacked on top of each other. The constructions are huge and there are many anthropologists who claim that these constructions are second in their greatness only to the great pyramids in Egypt because of how massive and unique they are.
I think the answers are A and D. Good luck I hope this helped.
A. True yes San Diego is a megalopolis
it pulled the usa out of the great depression and England boomed in manufacturing