A. Overland trade routes to Asia were controlled by the Ottoman Empire at that time.
Explanation:
During the 14th Century Ottomans started gaining control over the vast area that included Middle and Near East, Asia Minor, part of Balkan Peninsula. When they took Constantinople in 1453 they dominated the whole Mediterranean. The trade routes were in their control and it was not safe for merchants to pass through that area. That is why the Europeans started searching for a new sea route.
