The correct answer is 2. They didn't have the ships and navigation skills to travel around Africa to Asia.
The Age of Exploration was only possible as a result of new technology, that is, the inventions of new ships such as caravels or the extensive research of navigation by individuals like Prince Henry the Navigator. These two factors allowed explorers to count on further reliable means of transportation and a better understanding of the geography as well as conditions they would face during their expeditions.