Final answer:
The Kongo king whom the Portuguese had friendly relations with in the 1840s was King Affonso I.
Step-by-step explanation:
The correct answer is a) King Affonso I.
In the 1840s, the Portuguese had friendly relations with King Affonso I of the Kongo. He was the ruler of the Kongo kingdom in West Africa, and his letters to the Portuguese king discuss the loss of his kingdom and the need for a remedy.
King Affonso I tried to negotiate with the Portuguese as a peer, but he was unable to prevent Portuguese slave traders from taking people as slaves from his kingdom. The Portuguese brought the slaves to their sugar plantations in Brazil.