Final answer:
The sentence that best supports the idea that Olaudah was enslaved prior to being brought on board the ship is option c) Before boarding the ship, Olaudah was already in chains.
Step-by-step explanation:
The sentence that best supports the idea that Olaudah was enslaved prior to being brought on board the ship is option c) Before boarding the ship, Olaudah was already in chains.
This sentence suggests that Olaudah was already in chains, indicating that he was already enslaved before being taken aboard the ship. It provides direct evidence of his pre-existing enslavement.