How did the invention of the caravel make european expansion possible?

The caravel was created during the 15th century by the Portuguese.  It was a small but maneuverable ship that made use of lateen sails that gave it speed and windward sailing capacities.  It was developed by the Portuguese who used it for exploring the West African Coast as well as the Atlantic Ocean.  It was the vessel of choice for Portuguese travelers like Bartholomew Diaz, Vasco De Gama and Ferdinand Magellan.  It was agile and easier to navigate.  It also had a shallow keel it had the capacity to sail upriver even on shallow waters.

Ithink the answer should be a.