The correct answer is A) The civilization's ancient writing has not been deciphered.
Archaeologists and historians founded it difficult to compile extensive information about the Indus Valley civilization? because civilization's ancient writing has not been deciphered.
The Indus Valley Civilization or Harappa people is considered to be one of the oldest civilizations on planet Earth. So little has been known of this old civilization because archeologists have found a way to decipher its writing.
The Indus Valley settled in next to the Indus River in the region of Pakistan and North India. It is considered one of the oldest cultures on earth as long as the Sumerian in the Middle East and teh Ancient Egypt, settled next to the Nile River.