Answer: c. The magnetic compass
The compass is an instrument for navigation that shows direction according to the cardinal points (north, south, east and west). The compass was invented in China and was used as early as c. 206 BC. However, it was not adopted for navigation until the 11th century. It started to be used in Western Europe and the Islamic world around 1190. The compass was one of the most important inventions that allowed the Age of Discovery to take place.