While some houses were large with many rooms and up to three levels, other houses in the harappan cities were small and doubled as workshops. the most important buildings and the houses of rich citizens were located in the upper citadels. the smaller, less-sturdy houses of the poor were located in a separate part of the city. these houses in the lower part of the city were built close together, with very narrow lanes separating them from each other. based on this information, what can be concluded about the harappan civilization? a. the harappans lived in very small houses. b. the harappans had a system of upper and lower classes. c. the harappans all lived in the same kinds of houses. d. harappan houses were all large with a lot of open spaces.