Which chinese technological innovation had the most direct impact on european exploration in the 15th century

The Navigational compass; The compass was invented in China during the Han Dynasty between the 2nd century BC and the 12st century AD. Early compasses were used to choose acceptable areas for building houses, to search for rare gems and for growing crops. They were adapted later for navigation purposes during the Song Dynasty in the 11th century by the military.

The compass did not come to Europe until the 12th century AD. In the 15th century European voyages turned more to the open waters of the Atlantic Ocean. The last decade of the 15th century was extraordinary for the sudden urge to search for water routes to the orient. The first to accomplish this triumph ad open a route to India was Vasco da Gama in 1497. During the same period Columbus made three of his four voyages to the new world before 1500s; he used it to predict his arrival into the Americas. Columbus picked up his compass and set out on a mission to go around the world.

The role of the compass in all this new effort was of supreme importance; with the compass explorers knew they could keep track of their location and could return home.  

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the answer is b. hope this