The answer to the first choice, "exploit". Aside from meaning a remarkable or heroic act or deed, the word may also mean an act that is worthy of praise. To help you with this type of questions, there are several dictionaries online that you may look into.
C : Thé strengths, weaknesses, and motivations of the characters
Answer:
by explaining how a captive’s condition was assessed.
Explanation:
The author developed the central idea that transporting enslaved captives was a trade just like any other in "Captain Canot" or "Twenty Years of an African Slaver" by explaining how a captive’s condition was assessed.
Most trades or all trades have profit as its main driving force, and profit cannot be made if the goods you sell is not good enough, so slave masters had to assess a captive's condition to find out if he was good enough to make a profit or not just like any other trade.