How did the geography and climate of the Indian subcontinent influence the development of early civilizations there?

The geography of India greatly influenced the location of early settlements on the subcontinent. Both the Indus and the Ganges rivers carried rich silt from the mountains to the plains. When the rivers flooded, the silt spread over the plains and made the soil in the river valleys fertile for farming.

#2 the answer is d

#3 the answer is a

#4 the answer is b