Final answer:
Africans were brought on deck to get sun, dance for Europeans, and get fresh air, answering (d) All of the above.
Step-by-step explanation:
Africans were allowed to come on the deck of the vessel for multiple reasons. Primarily, this practice was done to allow them to get some fresh air and to engage in forced exercise, such as making them jump and dance, to maintain their muscle strength for a higher selling price.
Thus, the correct answer to the question is d. All of the above, as they were brought on deck to get some sun, to dance for the Europeans, and to get some fresh air.