Why was the location of istanbul important?

a. it prevented the ottomans from being attacked.
b. it controlled the only route to india.
c. it was located at the base of mountains.
d. it gave the ottomans easy access to trade routes.

D. It gave the Ottomans easy access to trade routes

Explanation:

Istanbul, formerly Constantinople, was a city of great importance. The reason for that was that the city was located right on the place that connects Europe and Asia, as well as connecting the Mediterranean Sea (through the Aegean Sea) with the Black Sea. It was one on the most important location when it came to trade between Europe and Asia, so once the Ottomans had it under their control, they pretty much had monopoly and total control of the most important trade root. This brought great wealth to the empire, making it one of the most formidable forces in the world.

just finished this it is b. centrifugal force