Which best describes why archeologist and historians do not have extensive information about the Indus Valley

There are alot of factors that make it hard for archeologist and historians to search about the indus valley. the most highlighted factors are the enigmatic nature of Indus valley civilization means there is no clear connection to any continuous literary traditions. they have a much harder time imagining the life of Mohenjo-Daro because there isn't any reliable information about the culture of it. the fact that they cannot read the language (s) of the Indus valley means a lot!