How did the geography of the indian sub-continent, during the reign of the gupta, contribute to the movement of the people and ideas?

1) the control of the asian trade routes meant that culture and ideas could flow freely through the empire.
2) the location of the empire between northern mountains and southern seas was subject to monsoons.
3) as the continent was enclosed by water on three sides, cultural exchange was limited.
4) the location of the empire made it significantly vulnerable to attacks from seafaring pirates and profiteers.