I assume its that they are poor
I believe it is C. Try and think about where you would naturally pause, you wouldn't say "Tourists in Mexico *pause* enjoy eating the rich, delicious food."
Throughout the novel Voltaire employs the element of setting to signify the importance of distorted societal values. Candide grows up in beautiful castle in Westphalia; he is a young man of suspicious birth. Voltaire begins with this setting so he can expose the warped values that are related to social status.
