Final answer:
Prince Henry of Portugal, known as "the Navigator", is best described as an exploration leader. He played a pivotal role in the advancement of Portuguese exploration and navigation, leading to groundbreaking expeditions along the African coast.
Step-by-step explanation:
The description that best fits Prince Henry of Portugal, called "the Navigator", is b) Exploration leader. Prince Henry was a central figure in the early days of the Portuguese Empire and was instrumental in the development of the exploration of Africa and the Atlantic. His dedication to the advancement of navigation led to the Portuguese exploration of the coast of Africa, with the dual goals of finding trade routes and spreading Christianity.
His involvement in these exploratory efforts and his establishment of a navigation school in Sagres, where he supported shipbuilders, cartographers, and instrument makers, solidified his nickname "the Navigator". Under his patronage, Portuguese mariners were able to navigate new routes to Africa, seeding Portugal's future as a trade empire in the subsequent centuries.