Why does the author choose specific quotatations or specific people to quote in a novel?

What type of persuasive appeal seeks to show that an argument is correct or valid

At one point in the memoir, the ship strikes a rock and begins to leak. how does diaz del castillo solve this problem? by tossing the fresh water overboard. by forcing the crew to pump out the water flooding by calling for to a portuguese diver. by praying to the almighty.

What reasons does the author give to support the claim that it is difficult for a message to move people to take action?