Hello!!
Answer:
I'm 98.99% sure that the answer you are looking for is B.
Step-by-step explanation:
I know that nobody traded slaves at the time because slave trading happened in the mid-17th century so A won't work.
C wouldn't be your answer either because people started traveling to the western hemisphere (aka the Americas) after the European "age of discovery" in the early 16th century and Prince Henry died in 1460.
And finally, D wouldn't be your answer because the Cape of Good Hope was established by the Dutch and Prince Henry was Portugues. Also, it was established in 1652, so D wouldn't be your answer either.
In conclusion, I'm almost completely sure that your answer would be B.
I hoped this helped you and/or anyone else stuck with this question!
Please correct me in anything if I'm wrong!
Have a good day/morning/noon/afternoon/evening/night or any other time your in!