The correct answer is D) New Technology
Explanation:
Europeans had been exploring the sea for centuries but their distance was limited to the boats and the technology of the time.
However, by the middle ages, many new inventions had made it easier to explore open seas. The compass was a Chinese invention that was used by the Arabs and eventually Europeans to improve navigation.
Before this, an old system of sighting stars was used but it had its limitations.
Eventually better materials were used to make ships not only larger but more efficient and durable.
On top of this new knowledge helped in the development of more accurate world maps that helped both sea and land exploration.