Answer:
The answers are C and E.
c) The soil became too salty for crops to grow;
e) People moved to more fertile regions of the subcontinent.
Step-by-step explanation:
The Indus River Valley civilization (3300-1300 BCE) used to use salt water on their agricultural system. So, as the times passes the salt overloaded the soil making it inappropriate to grow anything; thus forcing the civilization to move to more fertile regions in order to have more stable and abundant crops.