The correct answers are A and C. The Indus Valley Civilisation was a bronze-age civilisation that built major urban centers in northwestern India, along the Indus. They were very dependent on trade and were one of the first societies to have an standardized system of weights and measures and it's even possible they had a symbol-based writing system. Their cities seem to have been higly planned, in a grid structure, with a high priority for hygiene, having one of the world's first known urban sanitation system, and wells for individual homes or sometimes group of homes. As for option B, if the houses had been made out of wood there would hardly be any trace of them left.