What made the Indus Valley unique in comparison to the Ganges River valley?

	a.	The Indus Valley did not require the development of public works because of its natural water supply.
	b.	The Indus Valley developed its own culture in near isolation from other emerging societies.
	c.	The Indus Valley had plentiful water from the Himalayas that ensured flourishing vegetation.
	d.	The Indus Valley remained relatively poor and could not support large populations in cities.