The type of land form that most early cultures were attracted to was riverbeds. The correct option among all the options that are given in the question is option "D". It has been seen that the earliest civilizations of Harappa and Mohenjodaro were established near the Indus river. The riverbeds were fertile and good for irrigation.
C since in 2011, the South Sudanese voted on a referendum in which about 99% of the voters voted to separate from Sudan and to become an independent country.
