Which of the following statements about Harappan civilization is false?
A.) We have learned a great deal about them by deciphering their written language. B.) It began around 2500 BC and declined around 2000 BC.
C.) It is known for its construction and engineering.
D.)We do not really know why it declined.

The Harappan civilization was a civilization that developed in the South of Asia. It is believed this civilization was one of the earliest civilization as it began around 2600-2500 BC in its mature and ended around 2000 - 1900 BC. Additionally, the Harappan civilization has been known for its complex cities, indeed, the cities in this civilization were carefully planned, had complex architectural structures and even drainage systems. The remain fo this cities along with handicrafts and metallurgy objects have been the main sources for understanding the Harappan civilization, especially because the Harappan language and script remains mainly unciphered and due to this, information about the Harappan civilization including the reasons why they declined is unknown.

Therefore, the statement about this civilization that is false is "We have learned a great deal about them by deciphering their written language" because this language has not been deciphered yet and therefore, it has been not possible to learn about them by using their scripts.