iThe correct answer is the Gold Coast and the Cape Verde islands.
Indeed, Prince Henry wanted to circumvent the Muslim blockade of the Mediterranean and be able to import slaves and Gold from African without their intervention. The Portuguese founded a trade fort at the Bay of Arguin (modern day Mauritania). In 1444 they went around the Cap-Vert Peninsula and discovered the Cape Verde Islands in 1456. This strategy ruined some of the Barbary Kingdoms and made Portugal rich and powerful.
